Modified polyethylene blown film compositions having excellent bubble stability

ABSTRACT

The present invention relates to polyethylene compositions comprising one or more ethylene polymers and one or more dendritic hydrocarbon polymer modifiers, in particular, this invention further relates to polyethylene blends comprising one or more ethylene polymers and one or more dendritic hydrocarbon polymer modifiers, wherein the modifier has: 1) a g′ vis  value less than 0.75; 2) at least 0.6 ppm ester groups as determined by  1 H NMR; 3) a Tm of 100° C. or more; 4) an Mw of 50,000 g/mol or more, as determined by GPC; 5) an average number of carbon atoms between branch points of 70 or more as determined by  1 H NMR.

PRIORITY CLAIM

This application is a continuation-in-part of U.S. Ser. No. 13/302,446,filed Nov. 22, 2011, now U.S. Pat. No. 8,487,059 which is incorporatedby reference herein.

STATEMENT OF RELATED APPLICATIONS

This invention is related to U.S. Ser. No. 61/538,703, filed Sep. 23,2011 and U.S. Ser. No. 13/584,137, filed Aug. 13, 2012, entitled“MODIFIED POLYETHYLENE FILM COMPOSITIONS” which is a continuation inpart of U.S. Ser. No. 12/904,428, filed Oct. 14, 2010, published as US2011/0118420, which claims priority to and the benefit of 61/279,127,filed Oct. 16, 2009.

FIELD OF THE INVENTION

The present invention relates to branched modifiers, polyethylenecompositions comprising an ethylene based polymer, and a branchedmodifier and films thereof.

BACKGROUND OF THE INVENTION

For many polyolefin applications, including films and fibers, increasedmelt strength and good optical properties are desirable attributes. Ahigher melt strength allows fabricators to run their blown film lines ata faster rate. It also allows them to handle thicker films inapplications such as geomembranes.

Typical metallocene catalyzed polyethylenes (mPE) are somewhat moredifficult to process than low-density polyethylenes (LDPE) made in ahigh-pressure polymerization process. Generally, mPEs (which tend tohave narrow molecular weight distributions and low levels of branching)require more motor power and produce higher extruder pressures to matchthe extrusion rate of LDPEs. Typical mPEs also have lower melt strengthwhich, for example, adversely affects bubble stability during blown filmextrusion, and they are prone to melt fracture at commercial shearrates. On the other hand, mPEs exhibit superior physical properties ascompared to LDPEs. In the past, various levels of LDPE have been blendedwith the mPE to increase melt strength, to increase shear sensitivity,i.e., to increase flow at commercial shear rates in extruders; and toreduce the tendency to melt fracture. However, these blends generallyhave poor mechanical properties as compared with neat mPE. It has been achallenge to improve mPEs processability without sacrificing physicalproperties.

U.S. Patent Application Publication No. 2007/0260016 discloses blends oflinear low density polyethylene copolymers with other linear low densitypolyethylenes or very low density, low density, medium density, highdensity, and differentiated polyethylenes, as well as articles producedtherefrom.

U.S. Pat. No. 6,300,451 discloses ethylene/butene/1,9-decadienecopolymers, and ethylene hexene vinyl norbornene copolymers (see TablesI and II). The decadiene terpolymers disclosed are designed to be usedalone and not in blends for improved processability/property balance.The relatively high MI of the resins suggests that they would not besuitable in blends which exhibit improved extensional strain hardening.

Patil, et al., “Rheology of Polyethylenes with Novel Branching TopologySynthesized by Chain Walking Catalyst,” Macromolecules, 2005, 38, pp.10571-10579 discloses dendritic PE produced from chain walking catalyst.The dendritic PE prepared by chain walking catalysts has extensive shortand long chain branches with combined branch density of greater than 100branches per 1000 carbon. The extensive short chain branching leads toamorphous polymers which have limited use in mixtures withsemicrystalline polyethylene resins of commercial interest.Additionally, these polymers are prepared at low temperatures andextremely low pressures, both conditions that are not commerciallyattractive. Additionally, blends are not disclosed in this paper andthere is no mention of blown film compositions.

Ye, et al., “Chain-Topology-Controlled Hyperbranched Polyethylene asEffective Polymer Processing Aid (PPA) For Extrusion of a MetalloceneLinear-Low-Density Polyethylene (mLLDPE),” J. Rheol., 2008, 52, pp.243-260 discloses that the processability of Exceed™ 1018 Polyethylene,in terms of melt fracture, could be improved with an addition of thehyperbranched PEs made from chain walking polymerization at more than 3wt %. Because the hyperbranched PE is immiscible with mLLDPE, it wasspeculated that the hyperbranched PE forms phase-separated droplets,which can migrate to the die surface and form a lubricating layerpromoting extrudate slippage.

U.S. Pat. No. 6,870,010 discloses blown films with improved opticalproperties produced from blends of linear metallocene PE with high MWHDPE. While the optical properties as measured by haze are improved overunblended film composition, the mechanical properties as measured byDart Impact suffer a significant deterioration.

U.S. Patent Application Publication No. 2011/0118420 discloses dendritichydrocarbon polymer and process for the production thereof. U.S. PatentApplication Publication No. 2011/0118420 also states in the backgroundsection, that “ . . . [w]hile LCB technology has been a part of thepolyethylene industry since the 1930's, there is still a need to furtheroptimize the type and availability of LCB polyethylenes and otherpolymers. A useful, inexpensive blend additive in the form of a LCBpolymer could significant[ly] impact the processing/performance balancefor polyethylenes, particularly the multi-billion dollar market forpolyethylene films and molded articles. There could be even greater usein polypropylene, where there is currently little commercially viabletechnology for incorporating LCB. There is also a need for LCB polymersin the EPDM elastomer market.”

Other references of interest include: Guzman, et al. AIChE Journal May2010, vol. 56, No 5, pg. 1325-1333; U.S. Pat. Nos. 5,670,595; 6,509,431;6,870,010; 7,687,580; 6,355,757; 6,391,998; 6,417,281; 6,114,457;6,734,265; and 6,147,180.

We have discovered that certain branched hydrocarbon modifiers willadvantageously improve processability of polyethylene withoutsignificantly impacting its mechanical properties. Moreover, addition ofthese branched hydrocarbon modifiers provides a means to change suchproperties on a continuous scale, based on real-time needs, which istypically not possible due to the availability of only discretepolyethylene grades. Furthermore, a different set of relationshipsbetween processability and properties is obtained, compared to thoseavailable from traditional polyethylenes and their blends withconventional LDPE, which allows for new and advantageous properties ofthe fabricated articles.

More particularly, the present invention relates to polyethylenecompositions having improved properties such as melt strength orextensional strain hardening, without substantial loss in blown film,dart impact, MD tear, or other mechanical properties. Additionally, thefilms produced from these compositions exhibit surprisingly excellentoptical properties as measured by lower film haze.

Further, this invention relates to polyethylene compositions havingimproved bubble stability. Previous attempts to remedy the situation byaddition of long-chain-branched PEs such as LDPE or other branched PEs(U.S. Pat. No. 6,870,010) have resulted in decreased mechanicalproperties. Some of the blown films blended with branched PE additivesadditionally suffered from poor optical properties, e.g., the existenceof gel particles. There is an industry wide need to find modifiers thatimprove processability without loss in mechanical properties, and morepreferably with enhancement in one or more mechanical properties.

The current invention solves the problem by using a crystallinelong-chain-branched hyper branched polyethylene (disclosed in U.S.patent application Ser. No. 13/302,446) that is effective in improvingprocessability at very low concentration levels (1%). The films producedfrom the 1% blend of this crystalline long-chain-branched hyper branchedPE with Exceed™ 2018CA PE exhibit the following combination ofproperties, among other things, which have not been possible in theprior art: a) free of gel and excellent optical properties; b) improvedfilm processability in terms of bubble stability, film gauge variation;and c) enhanced MD/TD tear and no loss in most of the mechanicalproperties except impact strength.

SUMMARY OF THE INVENTION

This invention relates to polyethylene compositions comprising one ormore ethylene polymers and one or more dendritic hydrocarbon polymermodifiers.

This invention further relates to polyethylene blends comprising one ormore ethylene polymers and one or more dendritic hydrocarbon polymermodifiers, wherein the modifier has: 1) a g′_(vis) value less than 0.75;2) at least 0.6 ppm ester groups as determined by ¹H NMR; 3) a Tm of100° C. or more; 4) an Mw of 50,000 g/mol or more, as determined by GPC;and 5) an average number of carbon atoms between branch points of 70 ormore as determined by ¹H NMR.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 depicts an illustrative 3rd generation dendritic structure.

FIG. 2 depicts the reaction scheme of Example 1 herein.

FIG. 3 shows a representative structure of dendritic polymer synthesizedand corresponding ¹H NMR spectrum for Example 1 herein.

FIG. 4 depicts linker molecular weight (red) and insertion efficiencyT3/T2 (blue) versus catalyst loading (Cyclooctene/Catalyst) for Example1 herein.

FIG. 5 depicts the reaction scheme of Example 2 herein.

FIG. 6 shows ¹H NMR spectra of the dendritic polymer of Example 2 hereinbefore hydrogenation (top) and after hydrogenation (bottom) with peakassignments.

FIG. 7 shows that the neat dendritic PE synthesized exhibits extensionalhardening as measured by SER (Sentmanat Extensional Rheometer).

FIG. 8 shows that extensional strain hardening can be observed in mLLDPEcontaining 1% and 3% dendritic PE additives as measured by SER(Sentmanat Extensional Rheometer).

FIG. 9 shows overlaid DSC (Differential Scanning calorimetry) traces ofmLLDPE film, neat dendritic PE, and mLLDPE containing 1% dendritic PEadditive.

FIG. 10 depicts the reaction scheme of Example 3 herein.

FIG. 11 shows ¹H NMR partial spectrum of Example 3 herein beforehydrogenation with peak assignments.

FIG. 12 shows the extensional strain hardening observed in blends ofExceed™ 2018 LLDPE containing 3% Modifier DPEY3 as measured by SER(Sentmanat Extensional Rheometer).

FIG. 13 is infrared dichroism of neat Exceed™ 2018 Polyethylene blownfilm and 1% DPEY2 blend blown film.

FIG. 14 presents illustrations of Cayley tree topology.

FIG. 15 presents illustrations of Cayley tree layer numbers.

DEFINITIONS

An “olefin,” alternatively referred to as “alkene,” is a linear,branched, or cyclic compound of carbon and hydrogen having at least onedouble bond. For purposes of this specification and the claims appendedthereto, when a polymer or copolymer is referred to as comprising anolefin, including, but not limited to ethylene, hexene, and diene, theolefin present in such polymer or copolymer is the polymerized form ofthe olefin. For example, when a copolymer is said to have an “ethylene”content of 35 wt % to 55 wt %, it is understood that a mer unit in thecopolymer is derived from ethylene in the polymerization reaction andsaid derived units are present at 35 wt % to 55 wt %, based upon theweight of the copolymer. A “polymer” has two or more of the same ordifferent mer units. A “homopolymer” is a polymer having mer units thatare the same. A “copolymer” is a polymer having two or more mer unitsthat are different from each other. A “terpolymer” is a polymer havingthree mer units that are different from each other. The term “different”as used to refer to mer units indicates that the mer units differ fromeach other by at least one atom or are different isomerically.Accordingly, the definition of copolymer, as used herein, includesterpolymers and the like. Likewise, the definition of polymer, as usedherein, includes copolymers and the like. Thus, as used herein, theterms “polyethylene,” “ethylene polymer,” “ethylene copolymer,” and“ethylene based polymer” mean a polymer or copolymer comprising at least50 mol % ethylene units (preferably at least 70 mol % ethylene units,more preferably at least 80 mol % ethylene units, even more preferablyat least 90 mol % ethylene units, even more preferably at least 95 mol %ethylene units or 100 mol % ethylene units (in the case of ahomopolymer)). Furthermore, the term “polyethylene composition” means ablend containing one or more polyethylene components.

As used herein, the terms “polypropylene,” “propylene polymer,”“propylene copolymer,” and “propylene based polymer” mean a polymer orcopolymer comprising at least 50 mol % propylene units (preferably atleast 70 mol % propylene units, more preferably at least 80 mol %propylene units, even more preferably at least 90 mol % propylene units,even more preferably at least 95 mol % propylene units or 100 mol %propylene units (in the case of a homopolymer)).

As used herein, the terms “polybutene,” “butene polymer,” “butenecopolymer,” and “butene based polymer” mean a polymer or copolymercomprising at least 50 mol % butene units (preferably at least 70 mol %butene units, more preferably at least 80 mol % butene units, even morepreferably at least 90 mol % butene units, even more preferably at least95 mol % butene units or 100 mol % butene units (in the case of ahomopolymer)).

For purposes of this invention and the claims thereto, an “EP Rubber” isdefined to be a copolymer of ethylene and propylene, and, optionally,diene monomer(s), chemically crosslinked (i.e., cured) or not, where theethylene content is from 35 wt % to 80 wt %, the diene content is 0 wt %to 15 wt %, and the balance is propylene; and where the copolymer has aMooney viscosity, ML(1+4) @ 125° C. (measured according to ASTM D1646)of 15 to 100. For purposes of this invention and the claims thereto, an“EPDM” or “EPDM Rubber” is defined to be an EP Rubber having dienepresent.

For purposes of this invention and the claims thereto, an ethylenepolymer having a density of 0.86 g/cm³ or less is referred to as anethylene elastomer or elastomer; an ethylene polymer having a density ofmore than 0.86 to less than 0.910 g/cm³ is referred to as an ethyleneplastomer or plastomer; an ethylene polymer having a density of 0.910 to0.940 g/cm³ is referred to as a low density polyethylene; and anethylene polymer having a density of more than 0.940 g/cm³ is referredto as a high density polyethylene (HDPE). For these definitions, densityis determined using the method described under Test Methods below.

Polyethylene in an overlapping density range, i.e., 0.890 to 0.930g/cm³, typically from 0.915 to 0.930 g/cm³, which is linear and does notcontain long chain branching is referred to as “linear low densitypolyethylene” (LLDPE) and can be produced with conventionalZiegler-Natta catalysts, vanadium catalysts, or with metallocenecatalysts in gas phase reactors and/or in slurry reactors and/or withany of the disclosed catalysts in solution reactors. “mLLDPE” is anLLDPE made by a metallocene catalyst.

“Linear” means that the polyethylene has no long chain branches;typically referred to as a g′_(vis) of 0.95 or above, preferably 0.97 orabove, preferably 0.98 or above.

Composition Distribution Breadth Index (CDBI) is a measure of thecomposition distribution of monomer within the polymer chains and ismeasured by the procedure described in PCT publication WO 93/03093,published Feb. 18, 1993, specifically columns 7 and 8, as well as inWild et al, J. Poly. Sci., Poly. Phys. Ed., Vol. 20, p. 441 (1982) andU.S. Pat. No. 5,008,204, including that fractions having a weightaverage molecular weight (Mw) below 15,000 are ignored when determiningCDBI.

Mw is weight average molecular weight, Mn is number average molecularweight and Mz is z average molecular weight. MD is machine direction. TDis transverse direction.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to polyethylene compositions comprising one ormore ethylene polymers (preferably linear ethylene polymers) and one ormore dendritic hydrocarbon polymer modifiers (also referred to as the“modifier” or the “branched modifier”).

This invention further relates to polyethylene blends comprising one ormore ethylene polymers (preferably having a g′_(vis) of 0.95 or more)and one or more dendritic hydrocarbon polymer modifiers, wherein themodifier has: 1) a g′_(vis) value or 0.75 or less (preferably 0.70 orless, preferably 0.65 or less, preferably 0.60 or less, preferably 0.55or less, preferably 0.50 or less, preferably 0.45 or less, preferably0.40 or less, preferably 0.35 or less, preferably 0.30 or less); 2) atleast 0.6 ppm ester groups (preferably 0.75 or more, preferably 1.0 ormore, preferably 1.2 or more, preferably 1.50 or more) as determined by¹H NMR; 3) a Tm of 100° C. or more (preferably 110° C. or more,preferably 120° C. or more, preferably 125° C. or more) as determined byDSC; 4) an Mw of 50,000 g/mol or more (preferably 100,000 g/mol or more,preferably 150,000 g/mol or more, preferably 200,000 g/mol or more,preferably 500,000 or more) as determined by GPC; 5) an average numberof carbon atoms between the branch points of 70 or more (preferably from140 to 5400, preferably 215 to 3600, preferably 350 to 1800) asdetermined by ¹H NMR; 6) optionally, an Mw/Mn of 3 or more (preferably 4or more, preferably 5 or more, preferably 6 or more, preferably 7 ormore, preferably 8 or more, preferably 9 or more, preferably 10 or more,preferably 12 or more, preferably 15 or more, preferably 20 or more); 7)optionally, less than 5 short chain branches (preferably 4 or less,preferably 3 or less, preferably 2 or less, preferably 1 or less,preferably zero) per 1000 carbons as determined by ¹³C NMR; and 8)optionally, an average Mw between the branch points is from 1000 to100,000 g/mol (preferably from 2000 to 75,000, preferably 3000 to50,000, preferably 5000 to 25,000) as determined by ¹H NMR.

In another embodiment of the invention, this invention relates to acomposition comprising:

1) from 99.99 wt % to 50 wt % (preferably from 75 wt % to 99.9 wt %,preferably from 90 wt % to 99.9 wt %, preferably from 95 wt % to 99.5 wt%, preferably from 96 wt % to 99.5 wt %, preferably from 97 wt % to 99.5wt %, preferably from 98 wt % to 99 wt %), based upon the weight of theblend, of an ethylene polymer having:

a) a branching index, g′_(vis), (determined according the proceduredescribed in the Test Method section below) of 0.95 or more, preferably0.97 or more, preferably 0.98 or more, preferably 0.99 or more;

b) a density of 0.860 to 0.980 g/cc (preferably from 0.880 to 0.940g/cc, preferably from 0.900 to 0.935 g/cc, preferably from 0.910 to0.930 g/cc);

c) an Mw of 20,000 g/mol or more (preferably 20,000 to 2,000,000 g/mol,preferably 30,000 to 1,000,000 g/mol, more preferably 40,000 to 200,000g/mol, preferably 50,000 to 750,000 g/mol); and

2) from 0.01 wt % to 50 wt % (preferably from 0.1 wt % to 25 wt %,preferably from 0.1 wt % to 10 wt %, preferably from 0.25 wt % to 5 wt%, preferably from 0.5 wt % to 4 wt %, preferably from 0.5 wt % to 3 wt%, preferably from 0.5 wt % to 2 wt %), based upon the weight of theblend, of a dendritic hydrocarbon polymer modifier(s), wherein themodifier has: 1) a g′_(vis) value less than 0.75 (preferably less than0.65, preferably less than 0.55, preferably less than 0.45, preferablyless than 0.40); 2) a Cayley tree topology with a layer number of 2 ormore, preferably 3 or more, preferably 4 or more; 3) at least 0.6 ppm(preferably at least 10 ppm, preferably at least 100 ppm, preferably atleast 1000 ppm, preferably at least 5000 ppm) of ester groups (asdetermined by ¹H NMR); 4) optionally, a weight average molecular weightbetween the branch points of 1000 g/mol or more (preferably 3,000 g/molor more, preferably 5,000 g/mol or more); 5) optionally, a crystallinitygreater than 10% (preferably greater than 15%, preferably greater than20%, as determined by DSC as described below), and 6) optionally, a heatof fusion greater than 0 J/g, (preferably greater than 10 J/g,preferably greater than 60 J/g, preferably greater than 100 J/g, asdetermined by DSC as described below).

In another embodiment of the invention, the modifiers described hereincontain less than 0.6 ppm silicon, preferably less than 0.3 ppm silicon,preferably less than 0.1 ppm silicon, preferably 0 ppm silicon (asdetermined by ICPES (Inductively Coupled Plasma Emission Spectrometry)),which is described in J. W. Olesik, “Inductively Coupled Plasma-OpticalEmission Spectroscopy,” in the Encyclopedia of MaterialsCharacterization, C. R. Brundle, C. A. Evans, Jr. and S. Wilson, Eds.,Butterworth-Heinemann, Boston, Mass., 1992, pp. 633-644, is used todetermine the amount of an element in a material.

In another embodiment, the polyethylene/modifier compositions of thisinvention comprise less than 5 wt %, (preferably less than 1 wt %,preferably 0 wt %) propylene homopolymer or copolymer, based upon theweight of the composition.

In another embodiment, the polyethylene/modifier compositions of thisinvention comprise less than 5 wt %, (preferably less than 1 wt %,preferably 0 wt %) EP Rubber, based upon the weight of the composition.

In a preferred embodiment, this invention comprises a blend comprising:

a) any branched modifier described herein present at from 0.1 wt % to99.5 wt %, (preferably from 0.1 wt % to 25 wt %, preferably from 0.25 wt% to 10 wt %, preferably from 0.5 wt % to 5 wt %, preferably from 0.5 wt% to 4 wt %, preferably from 0.5 wt % to 3 wt %, preferably from 0.5 wt% to 2 wt %, based upon the weight of the blend); and

b) one or more ethylene polymers having a g′_(vis) of 0.95 or more, aCDBI of 60% or more and a density of 0.90 g/cc or more, wherein theethylene polymer has a g′_(vis) of at least 0.01 units higher than theg′_(vis) of the branched modifier (preferably at least 0.02, preferablyat least 0.03, preferably at least 0.04, preferably at least 0.05,preferably at least 0.1, preferably at least 0.2, preferably at least0.3, preferably at least 0.4, preferably at least 0.45 units higher).

Modified Blends

In a preferred embodiment, the blends comprising the polyethylene(preferably linear polyethylene) described herein and the branchedmodifier described herein are gel free. Specifically, the blendpreferably has 5 wt % or less of xylene insoluble material (preferablyless than 4 wt %, preferably less than 3 wt %, preferably less than 2 wt%, preferably less than 1 wt %). The blown film of the compositionsdescribed herein are preferably essentially free of defects, e.g., areoptically clear.

Preferably, the quality of the films, preferably blown films, comprisingthe compositions described herein can be characterized by a compositegel count, as described in U.S. Pat. No. 7,393,916 of less than 100(preferably less than 60, preferably less than 50, preferably less than40, preferably less than 35.

In a preferred embodiment of the invention, any film, preferably blownfilms, comprising the compositions described herein may have a FAR(“film appearance rating”, visual comparison test to known standards)value of greater than +20 in one embodiment, and greater than +30 inanother embodiment, and greater than +40 in yet another embodiment. AFAR value is typically obtained by comparing the extruded film to a setof reference film standards having the same thickness (typically 1.0 milthickness). For example, one may use the standards available from TheDow Chemical Company (citing Test Method PEG #510 FAR). The FAR test maybe conducted as described in U.S. Pat. No. 7,714,072.

In a preferred embodiment, the blends comprising the polyethylene(preferably linear polyethylene) described herein and the branchedmodifier described herein have good processability as indicated bystrain hardening ratio.

In a preferred embodiment, the blends comprising the polyethylene(preferably linear polyethylene) described herein and the branchedmodifier described herein have a strain hardening ratio (SHR) of 1.1 ormore, preferably 1.5 or more, preferably 2.0 or more, when theextensional viscosity is measured at a strain rate of 1 sec⁻¹ and at atemperature of 150° C. as describe below in the Test Methods.

In a preferred embodiment, the polyethylene compositions comprising oneor more ethylene polymers and one or more branched modifiers showcharacteristics of strain hardening in extensional flow. Strainhardening is observed as a sudden, abrupt upswing of the extensionalviscosity in the transient extensional viscosity vs. time plot. Thisabrupt upswing, away from the behavior of a linear viscoelasticmaterial, was reported in the 1960s for LDPE (reference: J. Meissner,Rheology Acta., Vol. 8, 78, 1969) and was attributed to the presence oflong branches in the polymer. In one embodiment, the inventivepolyethylene compositions have strain-hardening in extensionalviscosity. The strain-hardening ratio is preferably 1.2 or more,preferably 1.5 or more, more preferably 2.0 or more, and even morepreferably 2.5 or more, when the extensional viscosity is measured at astrain rate of 1 sec⁻¹ and at a temperature of 150° C.

In one embodiment, the melt strength of the blend is at least 5% higherthan the melt strength of ethylene polymer component(s) used in theblend.

Rheology of the inventive composition can be different from the rheologyof the ethylene polymer component, depending on the properties of thebranched modifier polymer. In one embodiment, the difference in complexshear viscosity between the inventive composition and ethylene polymercomponent(s) is less than 10%, preferably less than 5% at allfrequencies.

In another embodiment, the complex shear viscosity of the inventivepolyethylene composition is at least 10% higher than the complexviscosity of the ethylene polymer component(s) employed in the blendcomposition when the complex viscosity is measured at a frequency of 0.1rad/sec and a temperature of 190° C., and the complex viscosity of theinventive polyethylene composition is the same or less than the complexviscosity of the ethylene polymer component used in the blendcomposition when the complex viscosity is measured at a frequency of 398rad/sec and a temperature of 190° C. The complex shear viscosity ismeasured according to procedure described in the Test Method sectionbelow. Alternatively, the shear thinning ratio of the inventivecomposition is at least 10% higher than the shear thinning ratio of theethylene polymer component.

Preferably, the blend of the polyethylene and the modifier has a meltindex, as measured by ASTM D-1238 at 190° C. and 2.16 kg in the range offrom 0.01 dg/min to 100 dg/min in one embodiment, from 0.01 dg/min to 50dg/min in a more particular embodiment, from 0.02 dg/min to 20 dg/min inyet a more particular embodiment, from 0.03 dg/min to 2 dg/min in yet amore particular embodiment, and from 0.002 dg/min to 1 dg/min in yet amore particular embodiment.

Preferably, the HLMI, also referred to as the I21, (ASTM D 1238190° C.,21.6 kg) of the blend of the polyethylene and the modifier ranges from0.01 to 800 dg/min in one embodiment, from 0.1 to 500 dg/min in anotherembodiment, from 0.5 to 300 dg/min in yet a more particular embodiment,and from 1 to 100 dg/min in yet a more particular embodiment wherein adesirable range is any combination of any upper I21 limit with any lowerI21 limit.

Preferably, the blend of the polyethylene and the modifier has a meltindex ratio (MIR, or I21/I2, ASTM D 1238, 190° C., 21.6 kg/2.16 kg) offrom 10 to 500 in one embodiment, from 15 to 300 in a more particularembodiment, and from 20 to 200 in yet a more particular embodiment.Alternately, the modifiers may have a melt index ratio of from greaterthan 15 in one embodiment, greater than 20 in a more particularembodiment, greater than 30 in yet a more particular embodiment, greaterthan 40 in yet a more particular embodiment, and greater than 50 in yeta more particular embodiment.

Preferably, the blend of the polyethylene and the modifier is gel-free.Presence of gel can be detected by dissolving the material in xylene atxylene's boiling temperature. Gel-free product should be dissolved inxylene. In one embodiment, the branched modifier has 5 wt % or less(preferably 4 wt % or less, preferably 3 wt % or less, preferably 2 wt %or less, preferably 1 wt % or less, preferably 0 wt %) of xyleneinsoluble material.

In a preferred embodiment, this invention relates to a compositioncomprising more than 25 wt % (based on the weight of the composition) ofone or more ethylene polymers having a g′_(vis) of 0.95 or more and anM_(w) of 20,000 g/mol or more and at least 0.1 wt % of a dendritichydrocarbon polymer modifier where the modifier has a g′_(vis) of lessthan 0.75, wherein the ethylene polymer has a g′_(vis) of at least 0.2units higher than the g′_(vis) of the branched modifier, preferably atleast 0.25 higher, preferably at least 0.30 higher, preferably at least0.35 higher, preferably at least 0.40 higher.

In a preferred embodiment, films, preferably blown films, produced fromthe blend of polyethylene and modifier have an Elmendorf Tear, (reportedin grams (g) or grams per mil (g/mil) as determined by ASTM D-1922) ofat least 100 g/mil, preferably at least 150 g/mil, preferably at least200 g/mil, wherein a desirable blend may exhibit any combination of anyupper limit with any lower limit.

In a preferred embodiment, films, preferably blown films, produced fromthe blend of polyethylene and modifier has a haze, (measured accordingto ASTM D1003) of 25 or less, preferably 15 or less, preferably 10 orless.

In a preferred embodiment, films, preferably blown films, produced fromthe blends of polyethylene and modifier described herein has a Dart Drop(determined as described in the Test Methods below and reported as gramsper mil) of at least 100 g/mil, preferably at least 150, preferably atleast 200 g/mil.

In a preferred embodiment, films, preferably blown films, produced fromthe blends of polyethylene and modifier described herein are at least0.3 mils thick, preferably at least 0.5 mils thick, preferably at least1.0 mils thick, and preferably the films are less than 5 mils thick,preferably less than 3 mils thick, preferably less than 2 mils thick,wherein a desirable blend may exhibit any combination of any upper limitwith any lower limit.

Dendritic Hydrocarbon Polymer Modifiers

The polyethylene compositions of the present invention include adendritic hydrocarbon polymer modifier (also referred to as a “modifier”or a “branched modifier” or a “branched modifier polymer” or a“dendritic modifier” herein). It will be realized that the classes ofmaterials described herein that are useful as modifiers can be utilizedalone or admixed with other modifiers described herein in order toobtain desired properties.

Dendritic hydrocarbon polymers useful as modifiers herein are typicallyproduced in a one step process for making a dendritic hydrocarbonpolymer by metathesis insertion polymerization and thereafter optionallyhydrogenating the polymer. The process comprises polymerizing an amountof one or more cyclic olefins and one or more multi-functional(meth)acrylates in the presence of a metathesis catalyst and underconditions sufficient to produce the dendritic hydrocarbon polymer. Theone or more multi-functional (meth)acrylates preferably have afunctionality of 3 or higher. The dendritic hydrocarbon polymer is thenhydrogenated to form the substantially saturated dendritic hydrocarbonpolymer.

Dendritic hydrocarbon polymers useful as modifiers herein are typicallyproduced in a one step process by metathesis insertion copolymerizationof cyclic olefins and multi-functional (meth)acrylates in the presenceof a metathesis catalyst followed by direct hydrogenation in the samereactor. Unlike previously disclosed synthetic methods, this newsynthetic method constructs complex dendritic polyolefins in a singlestep using commercially available monomers and catalysts. A separatehydrogenation step is necessary to deliver fully saturated polyolefins,but it can be done in the same reaction vessel and solvent system, i.e.,a one pot method.

The cyclic olefins useful in the processes of this disclosure can be anycyclic olefins that are capable of ring opening and polymerization inthe presence of a metathesis catalyst. Illustrative cyclic olefinsinclude, for example, cyclooctene and its derivatives, cyclooctadiene,1,5-dimethylcyclooctadiene, norbornene and its derivatives, cyclicolefins with a suitable ring strain, bicyclic or multicyclic olefins,and the like. Cyclic olefins with sufficient ring strains for ringopening metathesis polymerization are preferred. The method of thisdisclosure allows the selection of cyclic olefin monomers for designingthe dendritic polyolefin backbone composition. Depending on themonomer(s) used, the final dendritic and hydrogenated polyolefins can becrystalline or amorphous. The cyclic olefins are conventional materialsknown in the art and commercially available.

The multi-functional (meth)acrylates useful in the processes of thisdisclosure can be any multi-functional acrylates or methacrylates thatare capable of insertion and polymerization with a cyclic olefin.Illustrative multi-functional (meth)acrylates include, for example,trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxylatetriacrylate, glycerol propoxylate (1PO/OH) triacrylate,1,3,5-triacryloylhexahydro-1,3,5-triazine, tris[2-(acryloyloxy)ethyl]isocyanurate, pentaerythritol tetraacrylate (PETA),di(trimethylolpropane)tetraacrylate, dipentaerythritol hexaacrylate(DPEHA), and the like. The functionality of the multi-functional(meth)acrylate is 3 or higher, in order to develop higher generation,greater than second-generation, dendritic polyolefins. Many tri-,tetra-, and even higher multi-functional (meth)acrylates arecommercially available at reasonable prices. Dendritic generations canbe tailored to third or higher with a proper selection of themulti-functional (meth)acrylate and other reaction conditions. Dendriticgeneration/branching density can also be adjusted by acrylic connectorchoice.

The concentration of the one or more cyclic olefins and one or moremulti-functional (meth)acrylates used in the process of this disclosurecan vary over a wide range and need only be concentrations sufficient toform the dendritic hydrocarbon polymer. The one or more cyclic olefinsand one or more multi-functional (meth)acrylates can be present in amolar concentration ratio (cyclic olefin/multi-functional(meth)acrylate) of from 2 and higher, preferably from 3 to 2000, andmore preferably from 50 to 200. Dendritic generations can be tailored tothird and higher with a proper selection of the cyclicolefin/multi-functional (meth)acrylate molar ratio.

For a first-generation dendritic polymer, the cyclicolefin/multi-functional (meth)acrylate molar ratio will range from 3 andhigher. For a second-generation polymer, the cyclicolefin/multi-functional (meth)acrylate molar ratio will range from 2.25and higher. For a third-generation dendritic polymer, the cyclicolefin/multi-functional (meth)acrylate molar ratio will range from 2.1and higher. For an infinite-generation dendritic polymer, the cyclicolefin/multi-functional (meth)acrylate molar ratio will range from 2 andhigher.

The metathesis catalyst can be any catalyst suitable for catalyzing themetathesis polymerization. Illustrative metathesis catalysts useful inthe process of this disclosure include, for example, Grubbs 1^(st)generation catalyst, Grubbs 2^(nd) generation catalyst, Hoveyda-Grubbscatalysts, ruthenium-based metathesis catalysts, and the like. Thecatalysts are conventional materials known in the art and commerciallyavailable.

In a preferred embodiment, the metathesis catalyst is one or more oftricyclohexylphosphine[1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene][3-phenyl-1H-inden-1-ylidene]ruthenium(II)dichloride,tricyclohexylphosphine[3-phenyl-1H-inden-1-ylidene][1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydro-imidazol-2-ylidene]ruthenium(II)dichloride,tricyclohexylphosphine[1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][(phenylthio)methylene]ruthenium(II)dichloride,bis(tricyclohexylphosphine)-3-phenyl-1H-inden-1-ylideneruthenium(II)dichloride,1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methyleneruthenium(II)dichloride,and[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]-[2-[[(4-methylphenyl)imino]methyl]-4-nitrophenolyl]-[3-phenyl-1H-inden-1-ylidene]ruthenium(II)chloride. In a preferred embodiment, the catalyst is1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methyleneruthenium(II)dichloride,and/ortricyclohexylphosphine[3-phenyl-1H-inden-1-ylidene][1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene]ruthenium(II)dichloride.

In another embodiment, the metathesis catalyst useful herein may be anyof the catalysts described in U.S. Pat. Nos. 6,111,121; 5,312,940;5,342,909; 7,329,758; 5,831,108; 5,969,170; 6,759,537; 6,921,735; andU.S. Patent Publication No. 2005-0261451 A1, including, but not limitedto:

-   benzylidene-bis(tricyclohexylphosphine)dichlororuthenium;-   benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2    imidazolidinylidene]dichloro(tricyclohexyl phosphine) ruthenium;-   dichloro(o-isopropoxyphenylmethylene)(tricyclohexylphosphine)ruthenium(II);-   (1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyphenylmethylene)ruthenium;-   1,3-bis(2-methylphenyl)-2-imidazolidinylidene]dichloro(2-isopropoxyphenylmethylene)    ruthenium(II);-   [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro[3-(2-pyridinyl)propylidene]ruthenium(II);-   [1,3-bis(2-methylphenyl)-2-imidazolidinylidene]dichloro(phenylmethylene)    (tricyclohexylphosphine)ruthenium(II);-   [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(3-methyl-2-butenylidene)    (tricyclohexylphosphine)ruthenium(II); and-   [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(benzylidene)bis(3-bromopyridine)ruthenium(II).

In a preferred embodiment, the metathesis catalyst compound comprisesone or more of:

-   2-(2,6-diethylphenyl)-3,5,5,5-tetramethylpyrrolidine[2-(i-propoxy)-5-(N,N-dimethylamino    sulfonyl)phenyl]methylene ruthenium dichloride;-   2-(mesityl)-3,3,5,5-tetramethylpyrrolidine[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)    phenyl]methylene ruthenium dichloride;-   2-(2-isopropyl)-3,3,5,5-tetramethylpyrrolidine[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)    phenyl]methylene ruthenium dichloride;-   2-(2,6-diethyl-4-fluorophenyl)-3,3,5,5-tetramethylpyrrolidine[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methylene    ruthenium dichloride; and mixtures thereof.

For further information on such metathesis catalysts, please see U.S.Pat. No. 8,063,232, claiming priority to and the benefit of U.S. PatentApplication 61/259,514, filed Nov. 9, 2009. Many of the above namedcatalysts are generally available from Sigma-Aldrich Corp. (St. Louis,Mo.) or Strem Chemicals, Inc. (Newburyport, Mass.).

The concentration of the metathesis catalyst used in the process of thisdisclosure can vary over a wide range and need only be a concentrationsufficient to catalyze the polymerization. The metathesis catalyst canbe present in an amount of from 0.00001 M to 1 M, preferably from 0.0001M to 0.1 M, and more preferably from 0.001 M to 0.01 M.

In the dendritic hydrocarbon polymers of this disclosure, the lengthbetween two branching points is tunable, which is controlled by catalystloading. Dendritic generation/branching density can be adjusted bycatalyst loading and/or acrylic connector choice.

The average linker length and insertion efficiency can be controlled bythe catalyst loading. Linker length increases with the decrease ofcatalyst loading. At the same time, a high full insertion ratio can beachieved at a certain catalyst loading.

The dendritic polyolefins prepared by the process of this disclosurepreferably have a dendritic generation of 2 (e.g., a Cayley treetopology of 2) and higher and have molecular weight between 5,000 to5,000,000 g/mol, and most preferably between 10,000 and 1,000,000 g/mol.Illustrative dendritic polyolefins prepared by the process describedherein are shown in FIG. 1.

In one embodiment of the invention, the dendritic structure is adendritic structure of at least generation 2 (e.g., a Cayley treetopology of at least 2). In another embodiment, the dendritic structureis a dendritic structure of at least generation 3 (e.g., a Cayley treetopology of at least 3).

The crystalline dendritic polyolefins of this disclosure can be used asa processability additive in a semi-crystalline polyolefin of similarbackbone composition for delivering extensional strain hardening, highermelt strength, and faster blown film processing speed at a concentrationof 0.1 wt % to 20 wt %, more preferably 0.25 wt % to 15 wt %, and mostpreferably 0.5 wt % to 10 wt %. The amorphous dendritic polyolefins ofthis disclosure can be used as a processability additive in anelastomeric polyolefin of similar backbone composition for deliveringextensional hardening and higher melt strength for better compoundingprocessability and cold flow resistance at a concentration of 0.1 wt %to 20 wt %, more preferably 0.25 wt % to 15 wt %, and most preferably0.5 wt % to 10 wt %. This amorphous dendritic polyolefin can also beused as a viscosity index improver in lubricants due to its temperatureinvariant solution coil dimension and its shear stability at aconcentration of 0.01 wt % to 7.5 wt %, more preferably 0.1 wt % to 5 wt%, and most preferably 0.3 wt % to 3 wt %.

Dendritic polyolefins of this disclosure with second and highergenerations are unique processability additives in polyolefins fordelivering extensional strain hardening, melt strength, and higher blownfilm processing speed. As described herein, dendritic polyethylenes ofsecond generation or higher have been prepared by anionic polymerizationand anionic condensation followed by hydrogenation. Both anionicpolymerization and anionic condensation methods involve more than threesynthetic steps including the synthesis of the di-functional initiatorand one hydrogenation step. Additionally, anionic methods are sensitiveto impurities and reactions can be slow or stopped with accumulation ofimpurities. In the process of this disclosure, a one step syntheticmethod has been developed for preparing dendritic polyolefins beforehydrogenation based on metathesis insertion copolymerization of cyclicolefins and multi-functional (meth)acrylates that have 3 or morefunctionalities. The dendritic polyolefin backbone composition, themolecular weight of the linker in between branching points, and thedendritic generation can be tailored based on the selection of cyclicolefin monomer, catalyst amount, cyclic olefin to multi-functional(meth)acrylate molar ratio, and the number of functionality on the(meth)acrylate. Additionally, hydrogenation can be carried out in thesame reactor immediately following the polymerization, to furnish fullysaturated polyolefins. Various commercial cyclic olefins andmulti-functional (meth)acrylates can be directly utilized in thesynthesis, to yield dendritic polyolefins of desirable structures.

Polymerization conditions for the reaction of the one or more cyclicolefins and one or more multi-functional (meth)acrylates, such astemperature, pressure, and contact time, may also vary greatly and anysuitable combination of such conditions may be employed herein. Thereaction temperature may range between −40° C. to 120° C., preferablybetween 15° C. to 100° C., and more preferably between 20° C. to 80° C.Normally the reaction is carried out under ambient pressure and thecontact time may vary from a matter of seconds or minutes to a few hoursor greater. The reactants can be added to the reaction mixture orcombined in any order. The stir time employed can range from 3 minutesto 168 hours, preferably from 10 minutes to 72 hours, and morepreferably from 30 minutes to 6 hours.

In this synthetic method, reactions are performed under ambient pressurewith a slight heating and are tolerant to ambient environment andimpurities. All monomers and solvents can be used as received withoutpurification.

Hydrogenation can be carried out in the process of the presentdisclosure by any known catalysis system, including heterogeneoussystems and soluble systems. Soluble systems are disclosed in U.S. Pat.No. 4,284,835 at column 1, line 65 through column 9, line 16 as well asU.S. Pat. No. 4,980,331 at column 3, line 40 through column 6, line 28.

For purposes of the present disclosure, “substantially saturated” as itrefers to the dendritic hydrocarbon polymer means that polymer includeson average fewer than 10 double bonds, or fewer than 5 double bonds, orfewer than 3 double bonds, or fewer than 1 double bond per 100 carbonsin a hydrocarbon polymer chain.

Additional teachings to hydrogenation are disclosed in Rachapudy et al.,Journal of Polymer Science Polymer Physics Edition, Vol. 17, 1211-1222(1979), which is incorporated herein by reference in its entirety. Table1 of the article discloses several systems including palladium onvarious supports (calcium carbonate, but also barium sulfide). TheRachapudy et al. article discloses preparation of homogeneous catalystsand heterogeneous catalysts.

The Rachapudy et al. article discloses a method of preparation of ahomogeneous catalyst. The catalyst can be formed by reaction between ametal alkyl and the organic salt of a transition metal. The metal alkylswere n-butyl lithium (in cyclohexane) and triethyl aluminum (in hexane).The metal salts were cobalt and nickel 2-ethyl hexanoates (inhydrocarbon solvents) and platinum and palladium acetyl-acetonates(solids). Hydrogenation was conducted in a 1-liter heavy-wall glassreactor, fitted with a stainless steel flange top and magneticallystirred. A solution of 5 grams of polybutadiene in 500 milliliters ofdry cyclohexane was added, and the reactor was closed and purged withnitrogen. The catalyst complex was prepared separately by adding thetransition metal salt to the metal alkyl in cyclohexane under nitrogen.The molar ratio of component metals (alkyl to salt) was generally 3.5/1,the optimum in terms of rate and completeness of hydrogenation. Thereactor was heated to 70° C., purged with hydrogen, and the catalystmixture (usually 0.03 moles of transition metal per mole of doublebonds) injected through a rubber septum. Hydrogen pressure was increasedto 20 psi (gauge) and the reaction allowed to proceed for approximately4 hours. Hydrogenation proceeds satisfactorily in the initial stageseven at room temperature, but the partially hydrogenated polymer soonbegins to crystallize. At 70° C., the polymer remains in solutionthroughout the reaction.

After hydrogenation the catalyst was decomposed with dilute HCl. Thepolymer was precipitated with methanol, washed with dilute acid,re-dissolved, re-precipitated, and dried under vacuum. Blank experimentswith polyethylene confirmed that the washing procedure was sufficient toremove any uncombined catalyst decomposition products.

The Rachapudy et al. article also discloses a method of preparation of aheterogeneous catalyst. A 1-liter high-pressure reactor (Parr InstrumentCo.) was used. The catalysts were nickel on kieselguhr (Girdler Co.) andpalladium on calcium carbonate (Strem Chemical Co.). Approximately 5grams of polybutadiene were dissolved in 500 milliliters of drycyclohexane, the catalyst was added (approximately 0.01 moles metal/moleof double bonds), and the reactor was purged with hydrogen. The reactorwas then pressurized with hydrogen and the temperature was raised to thereaction temperature for 3 to 4 hours. For the nickel catalyst, thereaction conditions were 700 psi H₂ and 160° C. For palladium, theconditions were 500 psi H₂ and 70° C.

After reaction, the hydrogen was removed and the solution filtered at70° C. The polymer was precipitated with methanol and dried undervacuum.

Additional teachings to hydrogenation processes and catalysts thereforare disclosed in U.S. Pat. Nos. 4,284,835 and 4,980,331, both of whichare incorporated herein by reference in their entirety.

The catalysts described herein can be used to hydrogenate hydrocarbonscontaining unsaturated carbon bonds. The unsaturated carbon bonds whichmay be hydrogenated include olefinic and acetylenic unsaturated bonds.The process is particularly suitable for the hydrogenation under mildconditions of hydrogenatable organic materials having carbon-to-carbonunsaturation, such as acyclic monoolefins and polyolefins, cyclicmonoolefins and polyolefins, and mixtures thereof. These materials maybe unsubstituted or substituted with additional non-reactive functionalgroups such as halogens, ether linkages or cyano groups. Exemplary ofthe types of carbon-to-carbon compounds useful herein are hydrocarbonsof 2 to 30 carbon atoms, e.g., olefinic compounds selected from acyclicand cyclic mono-, di-, and triolefins. The catalysts of this disclosureare also suitable for hydrogenating carbon-to-carbon unsaturation inpolymeric materials, for example, in removing unsaturation frombutadiene polymers and co-polymers such as styrene-butadiene-styrene.

The hydrogenation reaction herein is normally accomplished at atemperature from 40° C. to 160° C. and preferably from 60° C. to 150° C.Different substrates being hydrogenated will require different optimumtemperatures, which can be determined by experimentation. The initialhydrogenation pressures may range up to 3,000 psi partial pressure, atleast part of which is present due to the hydrogen. Pressures from 1 to7500 psig are suitable. Preferred pressures are up to 2000 psig, andmost preferred pressures are from 100 to 1000 psig are employed. Thereactive conditions are determined by the particular choices ofreactants and catalysts. The process may be either batch or continuous.In a batch process, reaction times may vary widely, such as between 0.01second to 10 hours. In a continuous process, reaction times may varyfrom 0.1 seconds to 120 minutes and preferably from 0.1 second to 10minutes.

The ratio of catalyst to material being hydrogenated is generally notcritical and may vary widely within the scope of the disclosure. Molarratios of catalyst to material being hydrogenated between 1:1000 and10:1 are found to be satisfactory; higher and lower ratios, however, arepossible.

If desired, the hydrogenation process may be carried out in the presenceof an inert diluent, for example, a paraffinic or cycloparaffinichydrocarbon.

Additional teachings to hydrogenation processes and catalysts thereforare disclosed in U.S. Pat. No. 4,980,331, which is incorporated hereinby reference in its entirety.

In general, any of the Group VIII metal compounds known to be useful inthe preparation of catalysts for the hydrogenation of ethylenicunsaturation can be used separately or in combination to prepare thecatalysts. Suitable compounds, then, include Group VIII metalcarboxylates having the formula (RCOO)_(n)M, wherein M is a Group VIIImetal, R is a hydrocarbyl radical having from 1 to 50 carbon atoms,preferably from 5 to 30 carbon atoms, and n is a number equal to thevalence of the metal M; alkoxides having the formula (RCO)_(n)M, whereinM is again a Group VIII metal, R is a hydrocarbon radical having from 1to 50 carbon atoms, preferably from 5 to 30 carbon atoms, and n is anumber equal to the valence of the metal M; chelates of the metalprepared with beta-ketones, alpha-hydroxycarboxylic acidsbeta-hydroxycarboxylic acids, beta-hydroxycarbonyl compounds, and thelike; salts of sulfur-containing acids having the general formulaM(SO_(x))_(n) and partial esters thereof; and salts of aliphatic andaromatic sulfonic acids having from 1 to 20 carbon atoms. Preferably,the Group VIII metal will be selected from the group consisting ofnickel and cobalt. Most preferably, the Group VIII metal will be nickel.

The metal carboxylates useful in preparing the catalyst include GroupVIII metal salts of hydrocarbon aliphatic acids, hydrocarboncycloaliphatic acids, and hydrocarbon aromatic acids. Examples ofhydrocarbon aliphatic acids include hexanoic acid, ethylhexanoic acid,heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoicacid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleicacid, and rhodinic acid. Examples of hydrocarbon aromatic acids includebenzoic acid and alkyl-substituted aromatic acids in which the alkylsubstitution has from 1 to 20 carbon atoms. Examples of cycloaliphaticacids include naphthenic acid, cyclohexylcarboxylic acid, andabietic-type resin acids. Suitable chelating agents which may becombined with various Group VIII metal compounds thereby yielding aGroup VIII metal chelate compound useful in the preparation of thecatalyst include beta-ketones, alpha-hydroxycarboxylic acids,beta-hydroxy carboxylic acids, and beta-hydroxycarbonyl compounds.Examples of beta-ketones that may be used include acetylacetone,1,3-hexanedione, 3,5-nonadione, methylacetoacetate, andethylacetoacetate. Examples of alpha-hydroxycarboxylic acids that may beused include lactic acid, glycolic acid, alpha-hydroxyphenylacetic acid,alpha-hydroxy-alpha-phenylacetic acid, and alpha-hydroxycyclohexylaceticacid. Examples of beta-hydroxycarboxylic acids include salicylic acidand alkyl-substituted salicylic acids. Examples of beta-hydroxylcarbonylcompounds that may be used include salicylaldehyde andθ-hydroxyacetophenone. The metal alkoxides useful in preparing thecatalysts include Group VIII metal alkoxides of hydrocarbon aliphaticalcohols, hydrocarbon cycloaliphatic alcohols, and hydrocarbon aromaticalcohols. Examples of hydrocarbon aliphatic alcohols include hexanol,ethylhexanol, heptanol, octanol, nonanol, decanol, and dodecanol. TheGroup VIII metal salts of sulfur-containing acids and partial estersthereof include Group VIII metal salts of sulfonic acid, sulfuric acid,sulphurous acid, and partial esters thereof. Of the sulfonic acids,aromatic sulfonic acids such as benzene sulfonic acid and p-toluenesulfonic acid are particularly useful.

In general, any of the alkylalumoxane compounds known to be useful inthe preparation of olefin polymerization catalysts may be used in thepreparation of the hydrogenation catalyst. Alkylalumoxane compoundsuseful in preparing the catalyst may, then, be cyclic or linear. Cyclicalkylalumoxanes may be represented by the general formula (R—Al—O)_(m)while linear alkylalumoxanes may be represented by the general formulaR(R—Al—O)_(n)AlR₂. In both of the general formulae R will be an alkylgroup having from 1 to 8 carbon atoms such as, for example, methyl,ethyl, propyl, butyl, and pentyl; m is an integer from 3 to 40; and n isan integer from 1 to 40. In a preferred embodiment, R will be methyl, mwill be a number from 5 to 20, and n will be a number from 10 to 20. Asis well known, alkylalumoxanes may be prepared by reacting an aluminumalkyl with water. Usually the resulting product will be a mixture ofboth linear and cyclic compounds.

Contacting of the aluminum alkyl and water may be accomplished inseveral ways. For example, the aluminum alkyl may first be dissolved ina suitable solvent such as toluene or an aliphatic hydrocarbon and thesolution then contacted with a similar solvent containing relativelyminor amounts of moisture. Alternatively, an aluminum alkyl may becontacted with a hydrated salt, such as hydrated copper sulfate orferrous sulfate. When this method is used, a hydrated ferrous sulfate isfrequently used. According to this method, a dilute solution of aluminumalkyl in a suitable solvent such as toluene is contacted with hydratedferrous sulfate. In general, 1 mole of hydrated ferrous sulfate will becontacted with from 6 to 7 moles of the aluminum trialkyl. When aluminumtrimethyl is the aluminum alkyl actually used, methane will be evolvedas conversion of the aluminum alkyl to an alkylalumoxane occurs.

In general, any of the Group Ia, IIa, or IIIa metal alkyls or hydridesknown to be useful in preparing hydrogenation catalysts in the prior artmay be used to prepare the catalyst. In general, the Group Ia, IIa, orIIIa metal alkyls will be peralkyls with each alkyl group being the sameor different containing from 1 to 8 carbon atoms and the hydrides willbe perhydrides although alkylhydrides should be equally useful.Aluminum, magnesium, and lithium alkyls and hydrides are particularlyuseful and these compounds are preferred for use in preparing thecatalyst. Aluminum trialkyls are most preferred.

The one or more alkylalumoxanes and the one or more Group Ia, IIa, orIIIa metal alkyls or hydrides may be combined and then contacted withthe one or more Group VIII metal compounds or the one or morealkylalumoxanes and the one or more Group Ia, IIa, or IIIa metal alkylsor hydrides may be sequentially contacted with the one or more GroupVIII metal compounds with the proviso that when sequential contacting isused, the one or more alkylalumoxanes will be first contacted with theone or more Group VIII metal compounds. Sequential contacting ispreferred. With respect to the contacting step the two differentreducing agents, i.e., the alkylalumoxanes and the alkyls or hydrides,might react with the Group VIII metal compound in such a way as to yielddifferent reaction products. The Group Ia, IIa, and IIIa metal alkylsand hydrides are a stronger reducing agent than the alkylalumoxanes,and, as a result, if the Group VIII metal is allowed to be completelyreduced with a Group Ia, IIa, or IIIa metal alkyl or hydride, thealkylalumoxanes might make little or no contribution. If the Group VIIImetal is first reduced with one or more alkylalumoxanes, the reactionproduct obtained with the alumoxane might be further reduced orotherwise altered by reaction with a Group Ia, IIa, or IIIa metal alkylor hydride.

Whether contacting is accomplished concurrently or sequentially, the oneor more alkylalumoxanes will be combined with the one or more Group VIIImetal compounds at a concentration sufficient to provide an aluminum toGroup VIII metal atomic ratio within the range from 1.5:1 to 20:1 andthe one or more Group Ia, IIa, or IIIa metal alkyls or hydrides will becombined with one or more Group VIII metal compounds at a concentrationsufficient to provide a Group Ia, IIa, or IIIa metal to Group VIII metalatomic ratio within the range from 0.1:1 to 20:1. Contact between theone or more Group VIII compounds and the one or more alkylalumoxanes andthe one or more alkyls or hydrides will be accomplished at a temperaturewithin the range from 20° C. and 100° C. Contact will typically becontinued for a period of time within the range from 1 to 120 minutes.When sequential contacting is used, each of the two contacting stepswill be continued for a period of time within this same range.

In general, the hydrogenation catalyst will be prepared by combining theone or more Group VIII metal compounds with the one or morealkylalumoxanes and the one or more Group Ia, IIa, or IIIa metal alkylsor hydrides in a suitable solvent. In general, the solvent used forpreparing the catalyst may be anyone of those solvents known in theprior art to be useful as solvents for unsaturated hydrocarbon polymers.Suitable solvents include aliphatic hydrocarbons such as hexane,heptane, and octane; cycloaliphatic hydrocarbons such as cyclopentaneand cyclohexane; alkyl-substituted cycloaliphatic hydrocarbons such asmethylcyclopentane, methylcyclohexane, and methylcyclooctane; aromatichydrocarbons such as benzene; hydroaromatic hydrocarbons such as decalinand tetralin; alkyl-substituted aromatic hydrocarbons such as tolueneand xylene; halogenated aromatic hydrocarbons such as chlorobenzene; andlinear and cyclic ethers such as the various dialkyl ethers, polyethers,particularly diethers, and tetrahydrofuran. Suitable hydrogenationcatalysts will usually be prepared by combining the catalyst componentsin a separate vessel prior to feeding the same to the hydrogenationreactor.

In a preferred embodiment of the invention, the modifier has:

1) a g′_(vis) value less than 0.75 (preferably less than 0.70,preferably less than 0.65, preferably less than 0.60, preferably lessthan 0.55, preferably less than 0.50, preferably less than 0.45,preferably less than 0.40, preferably less than 0.35, preferably lessthan 0.30); 2) a Cayley tree topology with a layer number of 2 or more,preferably 3 or more, preferably 4 or more; 3) at least 0.6 ppm(preferably at least 10 ppm, preferably at least 100 ppm, preferably atleast 1000 ppm, preferably at least 5000 ppm) of ester groups (asdetermined by ¹H NMR); 4) optionally, an average Mw between the branchpoints of 1,000 g/mol or more (preferably 3,000 g/mol or more,preferably 5,000 g/mol or more); 5) optionally, a crystallinity greaterthan 10% (preferably greater than 15%, preferably greater than 20%, asdetermined by DSC as described below); and 6) optionally, a heat offusion greater than 0 J/g, (preferably greater than 10 J/g, preferablygreater than 60 J/g, preferably greater than 100 J/g, as determined byDSC as described below).

In a preferred embodiment of the invention, the modifier has:

1) a g′_(vis) value or 0.75 or less (preferably 0.70 or less, preferably0.65 or less, preferably 0.60 or less, preferably 0.55 or less,preferably 0.50 or less, preferably 0.45 or less, preferably 0.40 orless, preferably 0.35 or less, preferably 0.30 or less); 2) at least 0.6ppm ester groups (preferably 0.75 or more, preferably 1.0 or more,preferably 1.2 or more, preferably 1.50 or more) as determined by ¹HNMR; 3) a Tm of 100° C. or more (preferably 110° C. or more, preferably120° C. or more, preferably 125° C. or more) as determined by DSC; 4) anMw of 50,000 g/mol or more (preferably 100,000 g/mol or more, preferably150,000 g/mol or more, preferably 200,000 g/mol or more, preferably500,000 or more) as determined by GPC; 5) an average number of carbonatoms between the branch points of 70 or more (preferably from 140 to5400, preferably 215 to 3600, preferably 350 to 1800) as determined by¹H NMR; 6) optionally, an Mw/Mn of 3 or more (preferably 4 or more,preferably 5 or more, preferably 6 or more, preferably 7 or more,preferably 8 or more, preferably 9 or more, preferably 10 or more,preferably 12 or more, preferably 15 or more, preferably 20 or more); 7)optionally, less than 5 short chain branches (preferably 4 or less,preferably 3 or less, preferably 2 or less, preferably 1 or less,preferably zero) per 1000 carbons as determined by ¹³C NMR; and 8)optionally, an average Mw between the branch points is from 1000 to100,000 g/mol (preferably from 2000 to 75,000, preferably 3000 to50,000, preferably 5000 to 25,000) as determined by ¹H NMR.

The average Mw between the branch points is determined by ¹H NMR on theunhydrogenated material using the integral ratio of the internalvinylene protons (for example, peak c in FIG. 6 a) to the double bondproton next to the carbonyl (for example, peak a in FIG. 6 a). Whenunhydrogenated material is unavailable, testing on the hydrogenatedmaterial uses the integral ratio of the all other alkyl protons (forexample, the peak at 1.5 ppm in FIG. 6 a) to the CH₂ proton next to theester (for example, peak d in FIG. 6 a). Average number of carbon atomsbetween the branch points is determined by dividing the average Mwbetween the branch points by 14.

The ¹³C NMR and ¹H NMR procedures are described below in the TestMethods section.

The dendritic hydrocarbon polymer modifiers used in this invention aredescribed as having a Cayley tree topology with at least two (preferablyat least three, preferably at least four) layers or having at least asecond (preferably at least third generation, preferably at least fourthgeneration) Cayley tree topology as referenced in Van Ruymbeke et al.Macromolecules, Vol. 40, No. 16, 2007 and Blackwell et al.,Macromolecules, 2001, 34, 2579-2596. Referring to FIG. 14, the threearmed material on the top left is referred to as having one layer, thestructure in the top middle is referred to as having two layers and thestructure on the top right is referred to as having three layers. Thestructures on the bottom left and right are examples of two and threelayer materials, even though each branch point is not symmetric. Forpurposes of this invention and the claims thereto, it is not necessarythat all branch points in the Cayley tree structure be symmetricallysubstituted. Missing tree branches due, for example, to the cappedconnector functionality or steric hindrance in affecting linkersreacting with one of the functionality on the connector is acceptable aslong as the layer number is 2 and above. The layer number affects therelaxation priority and is an important component in affecting theextensional relaxation. In any embodiment of the invention as describedherein, the dendritic hydrocarbon polymer modifiers may have a Cayleytree topology with at least four (alternately at least five) layers orhaving at least a fourth (preferably fifth) generation Cayley treetopology. The layer number is referred to as “n” in Blackwell et al.,Macromolecules, 2001, 34, 2579-2596. Using the assembly method withconnectors and linkers, the symmetric or asymmetric Cayley treestructures are achieved. The layer numbers can be determined based onmolecular weight fractionation (for example, where the modifier beginswith a tri-armed material, layer 2 will have an Mn roughly equal to thelinker Mn times 9 and layer 3 will have an Mn roughly equal to thelinker Mn times 21, etc.) and relaxation fractionation (based on SmallAmplitude Oscillatory Shear test where two relaxation peaks will befound for layer 2, 3 relaxation peaks will be detected for layer 3, andso on). Likewise, where the modifier begins with a tetra-armed material,layer 2 will have a Mn roughly equal to the linker Mn times 16 and layer3 will have a Mn roughly equal to the linker Mn times 52, etc., andrelaxation fractionation (based on Small Amplitude Oscillatory Sheartest where two relaxation peaks will be found for layer 2, 3 relaxationpeaks will be detected for layer 3, and so on).

In a preferred embodiment of the invention, any dendritic hydrocarbonpolymer modifier described herein has an average Mw of 1000 g/mol ormore, preferably 3,000 g/mol or more, preferably 5000 g/mol or morebetween branch points.

In any embodiment of the invention described herein, the dendritichydrocarbon polymer modifiers have:

i) a g′_(vis) of less than 0.75 (preferably less than 0.70, preferablyless than 0.65, preferably less than 0.60, preferably less than 0.55,preferably less than 0.50, preferably less than 0.45, preferably lessthan 0.40);

ii) a density of from about 0.880 to about 0.980 g/cm³ (preferably from0.890 to 0.940 g/cc, preferably from 0.900 to 0.935 g/cc, preferablyfrom 0.910 to 0.930 g/cc);

iii) a molecular weight distribution (Mw/Mn) of from about 1 to about 40(preferably 1.5 to 20, preferably 2.0 to 20); and

iv) optionally, less than 5 wt % xylene insoluble material (preferably 4wt % or less, preferably 3 wt % or less, preferably 2 wt % or less,preferably 1 wt % or less, preferably O wt %).

This invention further relates to a dendritic hydrocarbon polymermodifier where the modifier: a) has a g′_(vis) of 0.75 or less(preferably less than 0.70, preferably less than 0.65, preferably lessthan 0.60, preferably less than 0.55, preferably less than 0.50,preferably less than 0.45, preferably less than 0.40, preferably 0.35 orless, preferably 0.30 or less); b) is essentially gel free (preferably 5wt % or less of xylene insoluble material, preferably 4 wt % or less,preferably 3 wt % or less, preferably 2 wt % or less, preferably 1 wt %or less, preferably 0 wt %); c) has a Mw of 10,000 g/mol or more(preferably 25,000 or more, preferably 50,000 or more); d) a Cayley treetopology with 2 or more layers, preferably 3 or more layers, preferably4 or more layers; e) an average Mw between the branch points that isgreater than 1000 g/mol; f) an Hf greater than 0 J/g, greater than 20J/g; g) a percent crystallinity of 10% or more; h) a Mw/Mn of greaterthan 1 to less than 20, (preferably 1.2 to 15, preferably 1.5 to 10);and i) at least 0.6 ppm ester groups.

In a preferred embodiment of the invention, the modifiers comprise sidechain branches that are ethyl, butyl, or hexyl as determined by ¹³C NMRas described below.

In a preferred embodiment, the modifiers are dendritic hydrocarbonpolymers, preferably substantially saturated dendritic hydrocarbonpolymers, preferably saturated dendritic hydrocarbon polymers asdetermined by ¹³C NMR as described below.

The branched structure of the modifiers and the blends containing themodifiers can also be observed by Small Amplitude Oscillatory Shear(SAOS) measurement of the molten polymer performed on a dynamic(oscillatory) rotational rheometer. From the data generated by such atest it is possible to determine the phase or loss angle δ, which is theinverse tangent of the ratio of G″ (the loss modulus) to G′ (the storagemodulus). For a typical linear polymer, the loss angle at lowfrequencies (or long times) approaches 90 degrees, because the chainscan relax in the melt, adsorbing energy, and making the loss modulusmuch larger than the storage modulus. As frequencies increase, more ofthe chains relax too slowly to absorb energy during the oscillations,and the storage modulus grows relative to the loss modulus. Eventually,the storage and loss moduli become equal and the loss angle reaches 45degrees. In contrast, a branched chain polymer relaxes very slowly,because the branches need to retract first before the chain backbone canrelax along its tube in the melt. This polymer never reaches a statewhere all its chains can relax during an oscillation, and the loss anglenever reaches 90 degrees even at the lowest frequency, ω, of theexperiments. The loss angle is also relatively independent of thefrequency of the oscillations in the SAOS experiment; another indicationthat the chains can not relax on these timescales.

As known by one of skill in the art, rheological data may be presentedby plotting the phase angle versus the absolute value of the complexshear modulus (G*) to produce a van Gurp-Palmen plot. The plot ofconventional polyethylene polymers shows monotonic behavior and anegative slope toward higher G* values. Conventional LLDPE polymerswithout long chain branches exhibit a negative slope on the vanGurp-Palmen plot. The van Gurp-Palmen plots of some embodiments of thebranched modifier polymers described in the present disclosure exhibittwo slopes—a positive slope at lower G* values and a negative slope athigher G* values.

In a plot of the phase angle δ versus the measurement frequency ω,polymers that have long chain branches exhibit a plateau in the functionof δ(ω), whereas linear polymers do not have such a plateau. Accordingto Garcia-Franco et al. (Macromolecules 2001, 34, No. 10, 3115-3117),the plateau in the aforementioned plot will shift to lower phase anglesδ when the amount of long chain branching occurring in the polymersample increases. Dividing the phase angle at which the plateau occursby a phase angle of 90°, one obtains the critical relaxation exponent nwhich can then be used to calculate a gel stiffness using the equation:η*(ω)=SΓ(1−n)ω^(n-1)wherein η* represents the complex viscosity (Pa·s), ω represents thefrequency, S is the gel stiffness, Γ is the gamma function (see Beyer,W. H. Ed., CRC Handbook of Mathematical Sciences 5^(th) Ed., CRC Press,Boca Rotan, 1978), and n is the critical relaxation exponent. Modifiersuseful herein preferably have a gel stiffness of more than 150 Pa·s,preferably at least 300 Pa·s, and more preferably at least 500 Pa·s. Thegel stiffness is determined at the test temperature of 190° C. Apreferred critical relaxation exponent n for the modifiers useful hereinis less than 1 and more than 0, generally, n will be between 0.1 and0.92, preferably between 0.2 and 0.85.

Small amplitude oscillatory shear data can be transformed into discreterelaxation spectra using the procedure on pages 273-275 in R. B. Bird,R. C. Armstrong, and O. Hassager, Dynamics of Polymeric Liquids, Volume1, Fluid Mechanics, 2^(nd) Edition, John Wiley and Sons, (1987). Thestorage and loss moduli are simultaneously least squares fit with thefunctions,G′(ω_(j))=Ση_(k)λ_(k)ω_(j) ²/(1+(η_(k)ω_(k))²)G″(ω_(j))=Ση_(k)λ_(k)ω_(j)/(1+(η_(k)ω_(k))²)at the relaxation times λ_(k)=0.01, 0.1, 1, 10, and 100 seconds. Thesums are from k=1 to k=5. The sum of the η_(k)'s is equal to the zeroshear viscosity, η₀. An indication of high levels of branched blockproducts is a high value of η₅, corresponding to the relaxation time of100 s, relative to the zero shear viscosity. The viscosity fraction ofthe 100 s relaxation time is η₅ divided by the zero shear viscosity, η₀.

The modifiers used herein preferably have good shear thinning. Shearthinning is characterized by the decrease of the complex viscosity withincreasing shear rate. One way to quantify the shear thinning is to usea ratio of complex viscosity at a frequency of 0.01 rad/s to the complexviscosity at a frequency of 100 rad/s. Preferably, the complex viscosityratio of the modifier is 20 or more, more preferably 50 or more, evenmore preferably 100 or more when the complex viscosity is measured at190° C.

Shear thinning can be also characterized using a shear thinning index.The term “shear thinning index” is determined using plots of thelogarithm (base ten) of the dynamic viscosity versus logarithm (baseten) of the frequency. The slope is the difference in the log (dynamicviscosity) at a frequency of 100 rad/s and the log (dynamic viscosity)at a frequency of 0.01 rad/s divided by 4. These plots are the typicaloutput of small amplitude oscillatory shear (SAOS) experiments. Forpurposes of this invention, the SAOS test temperature is 190° C. forethylene polymers and blends thereof. Polymer viscosity is convenientlymeasured in Pascal*seconds (Pa*s) at shear rates within a range of from0.01 to 398 rad/sec and at 190° C. under a nitrogen atmosphere using adynamic mechanical spectrometer such as the Advanced RheometricsExpansion System (ARES). Generally, a low value of shear thinning indexindicates that the polymer is highly shear-thinning and that it isreadily processable in high shear processes, for example, by injectionmolding. The more negative this slope, the faster the dynamic viscositydecreases as the frequency increases. Preferably, the modifier has ashear thinning index of less than −0.2. These types of modifiers areeasily processed in high shear rate fabrication methods, such asinjection molding.

The branched modifier useful herein also preferably has characteristicsof strain hardening in extensional viscosity. An important feature thatcan be obtained from extensional viscosity measurements is the attributeof strain hardening in the molten state. Strain hardening is observed asa sudden, abrupt upswing of the extensional viscosity in the transientextensional viscosity vs. time plot. This abrupt upswing, away from thebehavior of a linear viscoelastic material, was reported in the 1960sfor LDPE (reference: J. Meissner, Rheol. Acta., Vol. 8, 78, 1969) andwas attributed to the presence of long branches in the polymer. Thestrain-hardening ratio (SHR) is defined as the ratio of the maximumtransient extensional viscosity over three times the value of thetransient zero-shear-rate viscosity at the same strain rate. Strainhardening is present in the material when the ratio is greater than 1.In one embodiment, the branched modifiers show strain-hardening inextensional flow. Preferably, the strain-hardening ratio is 2 orgreater, preferably 5 or greater, more preferably 10 or greater, andeven more preferably 15 or more, when extensional viscosity is measuredat a strain rate of 1 sec⁻¹ and at a temperature of 150° C.

The branched modifier also generally exhibits melt strength valuesgreater than that of conventional linear or long chain branchedpolyethylene of similar melt index. As used herein “melt strength”refers to the force required to draw a molten polymer extrudate at arate of 12 mm/s² at an extrusion temperature of 190° C. until breakageof the extrudate whereby the force is applied by take up rollers. In oneembodiment, the melt strength of the branched modifier polymer is atleast 20% higher than that of a linear polyethylene with the samedensity and MI.

In a preferred embodiment, the branched modifier has a strain hardeningratio of 5 or more, preferably 10 or more, preferably 20 or more,preferably 30 or more, preferably 40 or more, preferably 50 or more;and/or an Mw of 50,000 g/mol or more, preferably from 50,000 to2,000,000 g/mol, alternately from 100,000 to 1,000,000 g/mol,alternately from 150,000 to 750,000 g/mol.

Preferably, the modifier has a melt index as measured by ASTM D-1238 at190° C. and 2.16 kg in the range of from 0.01 dg/min to 100 dg/min inone embodiment, from 0.01 dg/min to 50 dg/min in a more particularembodiment, from 0.02 dg/min to 20 dg/min in yet a more particularembodiment, from 0.03 dg/min to 2 dg/min in yet a more particularembodiment, and from 0.002 dg/min to 1 dg/min in yet a more particularembodiment.

Preferably, the HLMI (ASTM D 1238190° C., 21.6 kg) of the modifierranges from 0.01 to 800 dg/min in one embodiment, from 0.1 to 500 dg/minin another embodiment, from 0.5 to 300 dg/min in yet a more particularembodiment, and from 1 to 100 dg/min in yet a more particularembodiment, wherein a desirable range is any combination of any upperI21 limit with any lower I21 limit.

The modifiers useful herein preferably have a melt index ratio (MIR, orI21/I2) of from 10 to 500 in one embodiment, from 15 to 300 in a moreparticular embodiment, and from 20 to 200 in yet a more particularembodiment. Alternately, the modifiers may have a melt index ratio offrom greater than 15 in one embodiment, greater than 20 in a moreparticular embodiment, greater than 30 in yet a more particularembodiment, greater than 40 in yet a more particular embodiment, andgreater than 50 in yet a more particular embodiment.

Preferably, the branched modifier is gel-free. Presence of gel can bedetected by dissolving the material in xylene at xylene's boilingtemperature. Gel-free product should be dissolved in xylene. In oneembodiment, the branched modifier has 5 wt % or less (preferably 4 wt %or less, preferably 3 wt % or less, preferably 2 wt % or less,preferably 1 wt % or less, preferably 0 wt %) of xylene insolublematerial.

The branched modifier preferably has an M_(w) of 10,000 to 2,000,000g/mol, preferably 20,000 to 1,000,000 g/mol, more preferably 30,000 to500,000 g/mol, as measured by size exclusion chromatography, asdescribed below in the Test Method section below; and/or an M_(w)/M_(n)of 2 to 40, preferably 2.5 to 30, more preferably 3 to 20, morepreferably 3 to 25 as measured by size exclusion chromatography; and/ora M_(z)/M_(w) of 2 to 50, preferably 2.5 to 30, more preferably 3 to 20,more preferably 3 to 25.

The branched modifier preferably has a density of 0.85 to 0.97 g/cm³,preferably 0.86 to 0.965 g/cm³, preferably 0.88 to 0.96 g/cm³,alternatively between 0.860 and 0.910 g/cm³, alternatively between 0.910and 0.940 g/cm³, or alternatively between 0.94 to 0.965 g/cm³(determined according to ASTM D 1505 using a density-gradient column ona compression-molded specimen that has been slowly cooled to roomtemperature (i.e., over a period of 10 minutes or more) and allowed toage for a sufficient time that the density is constant within +/−0.001g/cm³).

In a preferred embodiment, any branched modifier described herein has ag′_((Z ave)) of 0.90 or less, preferably 0.85 or less, preferably 0.80or less, preferably 0.75 or less, preferably 0.70 or less, preferably0.65 or less, preferably 0.60 or less.

Z average branching index (g′_((Z ave))) is determined using datagenerated using the SEC-DRI-LS-VIS procedure described in the TestMethods section, paragraph [0334] to [0341], pages 24-25 of U.S. PatentApplication Publication No. 2006/0173123 (including the references citedtherein, except that the GPC procedure is run as described in the TestMethods section below), where:

${g^{\prime}{Zave}} = \frac{\sum{C_{i}\left\lbrack \eta_{i} \right\rbrack}_{b}}{\sum{C_{i}{KM}_{i}^{\alpha}}}$where [η_(i)]_(b) is the viscosity of the polymer in slice i of thepolymer peak; M_(i) is the weight averaged molecular weight in slice iof the polymer peak measured by light scattering; K and a are theparameters for linear polyethylene (K=0.000579 and α=0.695); andC_(i)=polymer concentration in the slice i in the polymer peak times themass of the slice squared, M_(i) ².

In a preferred embodiment, the modifier has a shear thinning ratio ofcomplex viscosity at a frequency of 0.01 rad/sec to the complexviscosity at a frequency of 398 rad/sec greater than 53.9*I2^((−0.74)),where I2 is the melt index according to ASTM 1238 D, 190° C., 2.16 kg.

Ethylene Polymers

The modifiers described herein are blended with at least one ethylenepolymer to prepare the compositions of this invention.

In one aspect of the invention, the ethylene polymer is selected fromethylene homopolymer, ethylene copolymers, and blends thereof. Usefulcopolymers comprise one or more comonomers in addition to ethylene andcan be a random copolymer, a statistical copolymer, a block copolymer,and/or blends thereof. In particular, the ethylene polymer blendsdescribed herein may be physical blends or in situ blends of more thanone type of ethylene polymer or blends of ethylene polymers withpolymers other than ethylene polymers where the ethylene polymercomponent is the majority component (e.g., greater than 50 wt %). Themethod of making the polyethylene is not critical, as it can be made byslurry, solution, gas phase, high pressure, or other suitable processes,and by using catalyst systems appropriate for the polymerization ofpolyethylenes, such as Ziegler-Natta-type catalysts, chromium catalysts,metallocene-type catalysts, other appropriate catalyst systems, orcombinations thereof, or by free-radical polymerization. In a preferredembodiment, the ethylene polymers are made by the catalysts, activatorsand processes described in U.S. Pat. Nos. 6,342,566; 6,384,142;5,741,563; PCT publications WO 03/040201; and WO 97/19991. Suchcatalysts are well known in the art, and are described in, for example,ZIEGLER CATALYSTS (Gerhard Fink, Rolf Mülhaupt and Hans H. Brintzinger,eds., Springer-Verlag 1995); Resconi et al.; and I, II METALLOCENE-BASEDPOLYOLEFINS (Wiley & Sons 2000).

Preferred ethylene polymers and copolymers that are useful in thisinvention include those sold by ExxonMobil Chemical Company in HoustonTex., including those sold as ExxonMobil HDPE, ExxonMobil LLDPE, andExxonMobil LDPE; and those sold under the ENABLE™, EXACT™, EXCEED™,ESCORENE™, EXXCO™, ESCOR™, PAXON™, and OPTEMA™ tradenames.

In a preferred embodiment of the invention, the polyethylene copolymerspreferably have a composition distribution breadth index (CDBI) of 60%or more, preferably 60% to 80%, preferably 65% to 80%. In anotherpreferred embodiment, the ethylene copolymer has a density of 0.910 to0.950 g/cm³ (preferably 0.915 to 0.940 g/cm³, preferably 0.918 to 0.925g/cm³) and a CDBI of 60% to 80%, preferably between 65% and 80%.Preferably, these polymers are metallocene polyethylenes (mPEs).

In another embodiment, the ethylene copolymer comprises one or more mPEsdescribed in U.S. Patent Application Publication No. 2007/0260016 andU.S. Pat. No. 6,476,171, e.g., copolymers of an ethylene and at leastone alpha olefin having at least 5 carbon atoms obtainable by acontinuous gas phase polymerization using supported catalyst of anactivated molecularly discrete catalyst in the substantial absence of analuminum alkyl based scavenger (e.g., triethylaluminum,trimethylaluminum, tri-isobutyl aluminum, tri-n-hexylaluminum, and thelike), which polymer has a Melt Index of from 0.1 to 15 (ASTM D 1238,condition E); a CDBI of at least 70%, a density of from 0.910 to 0.930g/cc; a Haze (ASTM D1003) value of less than 20; a Melt Index ratio(I21/I2, ASTMD 1238) of from 35 to 80; an averaged Modulus (M) (asdefined in U.S. Pat. No. 6,255,426) of from 20,000 to 60,000 psi (13790to 41369 N/cm²) and a relation between M and the Dart Impact Strength(26 inch, ASTM D 1709) in g/mil (DIS) complying with the formula:DIS≧0.8×[100+e ^((11.71−0.000268×M+2.183×10) ⁻⁹ ^(×M) ² ⁾],where “e” represents 2.1783, the base Napierian logarithm, M is theaveraged Modulus in psi and DIS is the 26 inch (66 cm) dart impactstrength. (See U.S. Pat. No. 6,255,426 for further description of suchethylene polymers.)

In another embodiment, the ethylene polymer comprises a Ziegler-Nattapolyethylene, e.g., CDBI less than 50, preferably having a density of0.910 to 0.950 g/cm³ (preferably 0.915 to 0.940 g/cm³, preferably 0.918to 0.925 g/cm³).

In another embodiment, the ethylene polymer comprises olefin blockcopolymers as described in EP 1 716 190.

In another embodiment, the ethylene polymer is produced using chromebased catalysts, such as, for example, in U.S. Pat. No. 7,491,776including that fluorocarbon does not have to be used in the production.Commercial examples of polymers produced by chromium include the Paxon™grades of polyethylene produced by ExxonMobil Chemical Company, HoustonTex.

In another embodiment, the ethylene polymer comprises ethylene and anoptional comonomer of propylene, butene, pentene, hexene, octene noneneor decene, and said polymer has a density of more than 0.86 to less than0.910 g/cm³, an Mw of 20,000 g/mol or more (preferably 50,000 g/mol ormore), and a CDBI of 90% or more.

In another embodiment, the ethylene polymer comprises substantiallylinear ethylene polymers (SLEPs). Substantially linear ethylene polymersand linear ethylene polymers, and their method of preparation are fullydescribed in U.S. Pat. Nos. 5,272,236; 5,278,272; 3,645,992; 4,937,299;4,701,432; 4,937,301; 4,935,397; 5,055,438; and EP 129,368; EP 260,999;and WO 90/07526, which are fully incorporated herein by reference. Asused herein, “a linear or substantially linear ethylene polymer” means ahomopolymer of ethylene or a copolymer of ethylene and one or morealpha-olefin comonomers having a linear backbone (i.e., no crosslinking), a specific and limited amount of long-chain branching or nolong-chain branching, a narrow molecular weight distribution, a narrowcomposition distribution (e.g., for alpha-olefin copolymers), or acombination thereof. More explanation of such polymers is discussed inU.S. Pat. No. 6,403,692, which is incorporated herein by reference forall purposes.

Preferred ethylene homopolymers and copolymers useful in this inventiontypically have:

-   1. an M_(w) of 20,000 g/mol or more, 20,000 to 2,000,000 g/mol    preferably 30,000 to 1,000,000, preferably 40,000 to 200,000,    preferably 50,000 to 750,000, as measured by size exclusion    chromatography according to the procedure described below in the    Test Methods section; and/or-   2. an M_(w)/M_(n) of 1 to 40, preferably 1.6 to 20, more preferably    1.8 to 10, more preferably 1.8 to 4, preferably 8 to 25, as measured    by size exclusion chromatography as described below in the Test    Methods section; and/or-   3. a T_(m), of 30° C. to 150° C., preferably 30° C. to 140° C.,    preferably 50° C. to 140° C., more preferably 60° C. to 135° C., as    determined by the DSC method described below in the Test Methods    section; and/or-   4. a crystallinity of 5% to 80%, preferably 10% to 70%, more    preferably 20% to 60% (alternatively, the polyethylene may have a    crystallinity of at least 30%, preferably at least 40%,    alternatively at least 50%), where crystallinity is determined by    the DSC method described below in the Test Methods section; and/or-   5. a heat of fusion of 300 J/g or less, preferably 1 to 260 J/g,    preferably 5 to 240 J/g, preferably 10 to 200 J/g, as measured by    the DSC method described below in the Test Methods section; and/or-   6. a crystallization temperature (Tc) of 15° C. to 130° C.,    preferably 20° C. to 120° C., more preferably 25° C. to 110° C.,    more preferably 60° C. to 125° C., as measured by the method    described below in the Test Methods section; and/or-   7. a heat deflection temperature of 30° C. to 120° C., preferably    40° C. to 100° C., more preferably 50° C. to 80° C., as measured    according to ASTM D648 on injection molded flexure bars, at 66 psi    load (455 kPa); and/or-   8. a Shore hardness (D scale) of 10 or more, preferably 20 or more,    preferably 30 or more, preferably 40 or more, preferably 100 or    less, preferably from 25 to 75 (as measured by ASTM D 2240); and/or-   9. a percent amorphous content of at least 50%, alternatively at    least 60%, alternatively at least 70%, even more alternatively    between 50% and 95%, or 70% or less, preferably 60% or less,    preferably 50% or less, as determined by subtracting the percent    crystallinity from 100 as described in the Test Methods section    below; and/or-   10. a branching index (g′_(vis)) of 0.97 or more, preferably 0.98 or    more, preferably 0.99 or more, preferably 1, as measured using the    method described below in the Test Methods section; and/or-   11. a density of 0.860 to 0.980 g/cc (preferably from 0.880 to 0.940    g/cc, preferably from 0.900 to 0.935 g/cc, preferably from 0.910 to    0.930 g/cc) (alternately from 0.85 to 0.97 g/cm³, preferably 0.86 to    0.965 g/cm³, preferably 0.88 to 0.96 g/cm³, alternatively between    0.860 and 0.910 g/cm³, alternatively between 0.910 and 0.940 g/cm³,    or alternatively between 0.94 to 0.965 g/cm³) (determined according    to ASTM D 1505 using a density-gradient column on a    compression-molded specimen that has been slowly cooled to room    temperature (i.e., over a period of 10 minutes or more) and allowed    to age for a sufficient time that the density is constant within    +/−0.001 g/cm³).

The polyethylene may be an ethylene homopolymer, such as HDPE. Inanother embodiment the ethylene homopolymer has a molecular weightdistribution (M_(w)/M_(n)) of up to 40, preferably ranging from 1.5 to20, from 1.8 to 10 in another embodiment, from 1.9 to 5 in yet anotherembodiment, and from 2.0 to 4 in yet another embodiment. In anotherembodiment, the 1% secant modulus (determined according to ASTM D 882)of the ethylene polymer falls in a range of 200 to 1000 MPa, and from300 to 800 MPa in another embodiment, and from 400 to 750 MPa in yetanother embodiment, wherein a desirable polymer may exhibit anycombination of any upper flexural modulus limit with any lower flexuralmodulus limit. The melt index (MI) of preferred ethylene homopolymersrange from 0.05 to 800 dg/min in one embodiment, and from 0.1 to 100dg/min in another embodiment, as measured according to ASTM D1238 (190°C., 2.16 kg).

In a preferred embodiment, the polyethylene comprises less than 20 mol %propylene units (preferably less than 15 mol %, preferably less than 10mol %, preferably less than 5 mol %, preferably 0 mol % propyleneunits).

In another embodiment of the invention, the ethylene polymer is anethylene copolymer, either random, or block, of ethylene and one or morecomonomers selected from C₃ to C₂₀ α-olefins, typically from C₃ to C₁₀α-olefins in another embodiment. Preferably, the comonomers are presentfrom 0.1 wt % to 50 wt % of the copolymer in one embodiment, from 0.5 wt% to 30 wt % in another embodiment, from 1 wt % to 15 wt % in yetanother embodiment, and from 0.1 wt % to 5 wt % in yet anotherembodiment, wherein a desirable copolymer comprises ethylene and C₃ toC₂₀ α-olefin derived units in any combination of any upper wt % limitwith any lower wt % limit described herein. Preferably, the ethylenecopolymer will have a weight average molecular weight of from greaterthan 8,000 g/mol in one embodiment, greater than 10,000 g/mol in anotherembodiment, greater than 12,000 g/mol in yet another embodiment, greaterthan 20,000 g/mol in yet another embodiment, less than 1,000,000 g/molin yet another embodiment, and less than 800,000 g/mol in yet anotherembodiment, wherein a desirable copolymer may comprise any uppermolecular weight limit with any lower molecular weight limit describedherein.

In another embodiment, the ethylene copolymer comprises ethylene and oneor more other monomers selected from the group consisting of C₃ to C₂₀linear, branched or cyclic monomers, and in some embodiments is a C₃ toC₁₂ linear or branched alpha-olefin, preferably butene, pentene, hexene,heptene, octene, nonene, decene, dodecene, 4-methyl-pentene-1,3-methylpentene-1,3,5,5-trimethyl-hexene-1, and the like. The monomers may bepresent at up to 50 wt %, preferably from 0 wt % to 40 wt %, morepreferably from 0.5 wt % to 30 wt %, more preferably from 2 wt % to 30wt %, more preferably from 5 wt % to 20 wt %.

Preferred linear alpha-olefins useful as comonomers for the ethylenecopolymers useful in this invention include C₃ to C₈ alpha-olefins, morepreferably 1-butene, 1-hexene, and 1-octene, even more preferably1-hexene. Preferred branched alpha-olefins include 4-methyl-1-pentene,3-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene, 5-ethyl-1-nonene.Preferred aromatic-group-containing monomers contain up to 30 carbonatoms. Suitable aromatic-group-containing monomers comprise at least onearomatic structure, preferably from one to three, more preferably aphenyl, indenyl, fluorenyl, or naphthyl moiety. Thearomatic-group-containing monomer further comprises at least onepolymerizable double bond such that after polymerization, the aromaticstructure will be pendant from the polymer backbone. The aromatic-groupcontaining monomer may further be substituted with one or morehydrocarbyl groups including, but not limited to, C₁ to C₁₀ alkylgroups. Additionally, two adjacent substitutions may be joined to form aring structure. Preferred aromatic-group-containing monomers contain atleast one aromatic structure appended to a polymerizable olefinicmoiety. Particularly, preferred aromatic monomers include styrene,alpha-methylstyrene, para-alkylstyrenes, vinyltoluenes,vinylnaphthalene, allyl benzene, and indene, especially styrene,paramethyl styrene, 4-phenyl-1-butene, and allyl benzene.

Preferred diolefin monomers useful in this invention include anyhydrocarbon structure, preferably C₄ to C₃₀, having at least twounsaturated bonds, wherein at least two of the unsaturated bonds arereadily incorporated into a polymer by either a stereospecific or anon-stereospecific catalyst(s). It is further preferred that thediolefin monomers be selected from alpha, omega-diene monomers (i.e.,di-vinyl monomers). More preferably, the diolefin monomers are lineardi-vinyl monomers, most preferably those containing from 4 to 30 carbonatoms. Examples of preferred dienes include butadiene, pentadiene,hexadiene, heptadiene, octadiene, nonadiene, decadiene, undecadiene,dodecadiene, tridecadiene, tetradecadiene, pentadecadiene,hexadecadiene, heptadecadiene, octadecadiene, nonadecadiene, icosadiene,heneicosadiene, docosadiene, tricosadiene, tetracosadiene,pentacosadiene, hexacosadiene, heptacosadiene, octacosadiene,nonacosadiene, triacontadiene, particularly preferred dienes include1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene,1,13-tetradecadiene, and low molecular weight polybutadienes (M_(w) lessthan 1000 g/mol). Preferred cyclic dienes include cyclopentadiene,vinylnorbornene, norbornadiene, ethylidene norbornene, divinylbenzene,dicyclopentadiene, or higher ring containing diolefins with or withoutsubstituents at various ring positions.

In a particularly desirable embodiment, the ethylene polymer used hereinis a plastomer having a density of 0.91 g/cm³ or less, as determined byASTM D1505, and a melt index (MI) between 0.1 and 50 dg/min, asdetermined by ASTM D1238 (190° C., 2.16 kg). In one embodiment, theuseful plastomer is a copolymer of ethylene and at least one C₃ to C₁₂α-olefin, preferably C₄ to C₈ α-olefins. The amount of C₃ to C₁₂α-olefin present in the plastomer ranges from 2 wt % to 35 wt % in oneembodiment, from 5 wt % to 30 wt % in another embodiment, from 15 wt %to 25 wt % in yet another embodiment, and from 20 wt % to 30 wt % in yetanother embodiment.

Preferred plastomers useful in the invention have a melt index ofbetween 0.1 and 40 dg/min in one embodiment, from 0.2 to 20 dg/min inanother embodiment, and from 0.5 to 10 dg/min in yet another embodiment.The average molecular weight of preferred plastomers ranges from 10,000to 800,000 g/mole in one embodiment, and from 20,000 to 700,000 g/molein another embodiment. The 1% secant modulus (ASTM D 882) of preferredplastomers ranges from 5 MPa to 100 MPa in one embodiment and from 10MPa to 50 MPa in another embodiment. Further, preferred plastomers thatare useful in compositions of the present invention have a meltingtemperature (T_(m)) of from 30° C. to 100° C. in one embodiment, andfrom 40° C. to 80° C. in another embodiment. The degree of crystallinityof preferred plastomers is between 3% and 30%.

Particularly, preferred plastomers useful in the present invention aresynthesized using a single-site catalyst, such as a metallocenecatalyst, and comprise copolymers of ethylene and higher α-olefins, suchas propylene, 1-butene, 1-hexene and 1-octene, and which contain enoughof one or more of these comonomer units to yield a density between 0.86and 0.91 g/cm³ in one embodiment. The molecular weight distribution(M_(w)/M_(n)) of desirable plastomers ranges from 1.5 to 5 in oneembodiment and from 2.0 to 4 in another embodiment. Examples ofcommercially available plastomers are EXACT™ 4150, a copolymer ofethylene and 1-hexene, the 1-hexene derived units making up from 18 wt %to 22 wt % of the plastomer and having a density of 0.895 g/cm³ and MIof 3.5 dg/min (ExxonMobil Chemical Company, Houston, Tex.); and EXACT™8201, a copolymer of ethylene and 1-octene, the 1-octene derived unitsmaking up from 26 wt % to 30 wt % of the plastomer, and having a densityof 0.882 g/cm³ and MI of 1.0 dg/min (ExxonMobil Chemical Company,Houston, Tex.).

The melt index (MI) of preferred ethylene polymers, as measuredaccording to ASTM D1238 (190° C., 2.16 kg), ranges from 0.02 dg/min to800 dg/min in one embodiment, from 0.05 to 500 dg/min in anotherembodiment, and from 0.1 to 100 dg/min in another embodiment. In anotherembodiment of the present invention, the polyethylene has a MI of 20dg/min or less, 7 dg/min or less, 5 dg/min or less, 2 dg/min or less, orless than 2 dg/min. In yet another embodiment, the polymer has a Mooneyviscosity, ML(1+4) @ 125° C. (measured according to ASTM D1646) of 100or less, 75 or less, 60 or less, or 30 or less.

In yet another embodiment, the 1% secant modulus of preferred ethylenepolymers ranges from 5 MPa to 1000 MPa, from 10 MPa to 800 MPa inanother embodiment, and from MPa to 200 MPa in yet another embodiment,wherein a desirable polymer may exhibit any combination of any upperflexural modulus limit with any lower flexural modulus limit.

The crystallinity of the polymer may also be expressed in terms ofcrystallinity percent. The thermal energy for the highest order ofpolyethylene is estimated at 290 J/g. That is, 100% crystallinity isequal to 290 J/g. Preferably, the polymer has a crystallinity (asdetermined by DSC as described in the Test methods section below) withinthe range having an upper limit of 80%, 60%, 40%, 30%, or 20%, and alower limit of 1%, 3%, 5%, 8%, or 10%. Alternately, the polymer has acrystallinity of 5% to 80%, preferably 10% to 70, more preferably 20% to60%. (Alternatively, the polyethylene may have a crystallinity of atleast 30%, preferably at least 40%, alternatively at least 50%, wherecrystallinity is determined.)

The level of crystallinity may be reflected in the melting point. In oneembodiment of the present invention, the ethylene polymer has a singlemelting point. Typically, a sample of ethylene copolymer will showsecondary melting peaks adjacent to the principal peak, which isconsidered together as a single melting point. The highest of thesepeaks is considered the melting point. The polymer preferably has amelting point (as determined by DSC as described in the Test methodssection below) ranging from an upper limit of 150° C., 130° C., or 100°C. to a lower limit of 0° C., 30° C., 35° C., 40° C., or 45° C.

Preferred ethylene copolymers useful herein are preferably a copolymercomprising at least 50 wt % ethylene and having up to 50 wt %,preferably 1 wt % to 35 wt %, even more preferably 1 wt % to 6 wt %, ofa C₃ to C₂₀ comonomer (preferably hexene or octene), based upon theweight of the copolymer. The polyethylene copolymers preferably have acomposition distribution breadth index (CDBI) of 60% or more, preferably60% to 80%, preferably 65% to 80%. In another preferred embodiment, theethylene copolymer has a density of 0.910 to 0.950 g/cm³ (preferably0.915 to 0.940 g/cm³, preferably 0.918 to 0.925 g/cm³) and a CDBI of 60%to 80%, preferably between 65% and 80%. Preferably, these polymers aremetallocene polyethylenes (mPEs).

Further useful mPEs include those described in U.S. Patent ApplicationPublication No. 2007/0260016 and U.S. Pat. No. 6,476,171, e.g.,copolymers of an ethylene and at least one alpha olefin having at least5 carbon atoms obtainable by a continuous gas phase polymerization usingsupported catalyst of an activated molecularly discrete catalyst in thesubstantial absence of an aluminum alkyl based scavenger (e.g.,triethylaluminum, trimethylaluminum, tri-isobutyl aluminum,tri-n-hexylaluminum, and the like), which the polymer has a Melt Indexof from 0.1 to 15 (ASTM D 1238, condition E); a CDBI of at least 70%; adensity of from 0.910 to 0.930 g/cc; a Haze (ASTM D1003) value of lessthan 20; a Melt Index ratio (I21/I1, ASTMD 1238) of from 35 to 80; anaveraged Modulus (M) (as defined in U.S. Pat. No. 6,255,426) of from20,000 to 60,000 psi (13790 to 41369 N/cm²); and a relation between Mand the Dart Impact Strength (26 inch, ASTM D 1709) in g/mil (DIS)complying with the formula:DIS≧0.8×[100+e ^((11.71−0.000268×M+2.183×10) ⁻⁹ ^(×M) ² ⁾],where “e” represents 2.1783, the base Napierian logarithm, M is theaveraged Modulus in psi, and DIS is the 26 inch (66 cm) dart impactstrength.

Useful mPE homopolymers or copolymers may be produced using mono- orbis-cyclopentadienyl transition metal catalysts in combination with anactivator of alumoxane and/or a non-coordinating anion in solution,slurry, high pressure, or gas phase. The catalyst and activator may besupported or unsupported and the cyclopentadienyl rings may besubstituted or unsubstituted. Several commercial products produced withsuch catalyst/activator combinations are commercially available fromExxonMobil Chemical Company in Baytown, Tex. under the tradename EXCEED™Polyethylene or ENABLE™ Polyethylene.

Additives

The polyethylene compositions of the present invention may also containother additives. Those additives include antioxidants; nucleatingagents; acid scavengers; stabilizers; anticorrosion agents;plasticizers; blowing agents; cavitating agents; surfactants; adjuvants;block; antiblock; UV absorbers, such as, chain-breaking antioxidants,oils, etc.; quenchers; antistatic agents; slip agents; processing aids;UV stabilizers; neutralizers; lubricants; waxes; color masterbatches;pigments; dyes and fillers; and cure agents, such as, peroxide. In apreferred embodiment, the additives may each individually present at0.01 wt % to 50 wt % in one embodiment, from 0.01 wt % to 10 wt % inanother embodiment, and from 0.1 wt % to 6 wt % in another embodiment,based upon the weight of the composition. In a preferred embodiment,dyes and other colorants common in the industry may be present from 0.01wt % to 10 wt % in one embodiment and from 0.1 wt % to 6 wt % in anotherembodiment, based upon the weight of the composition. Preferred fillers,cavitating agents, and/or nucleating agents include titanium dioxide,calcium carbonate, barium sulfate, silica, silicon dioxide, carbonblack, sand, glass beads, mineral aggregates, talc, clay, and the like.

In particular, antioxidants and stabilizers, such as, organicphosphites, hindered amines, and phenolic antioxidants, may be presentin the polyethylene compositions of the invention from 0.001 wt % to 2wt %, based upon the weight of the composition, in one embodiment; from0.01 wt % to 0.8 wt % in another embodiment; and from 0.02 wt % to 0.5wt % in yet another embodiment. Non-limiting examples of organicphosphites that are suitable are tris(2,4-di-tert-butylphenyl)phosphite(IRGAFOS 168) and di(2,4-di-tert-butylphenyl)pentaerithritol diphosphite(ULTRANOX 626). Non-limiting examples of hindered amines includepoly[2-N,N′-di(2,2,6,6-tetramethyl-4-piperidinyl)-hexanediamine-4-(1-amino-1,1,3,3-tetramethylbutane)sym-triazine](CHIMASORB 944) and bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate(TINUVIN 770). Non-limiting examples of phenolic antioxidants includepentaerythrityl tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl) propionate(IRGANOX 1010) and1,3,5-Tri(3,5-di-tert-butyl-4-hydroxybenzyl-isocyanurate (IRGANOX 3114).

Fillers may be present from 0.001 wt % to 50 wt % in one embodiment,from 0.01 wt % to 25 wt %, based upon the weight of the composition, inanother embodiment, and from 0.2 wt % to 10 wt % in yet anotherembodiment. Desirable fillers include, but are not limited to, titaniumdioxide; silicon carbide; silica (and other oxides of silica,precipitated or not); antimony oxide; lead carbonate; zinc white;lithopone; zircon; corundum; spinel; apatite; Barytes powder; bariumsulfate; magnesiter; carbon black; dolomite; calcium carbonate; talc andhydrotalcite compounds of the ions Mg, Ca, or Zn with Al, Cr, or Fe andCO₃, and/or HPO₄, hydrated or not; quartz powder; hydrochloric magnesiumcarbonate; glass fibers; clays; alumina and other metal oxides andcarbonates; metal hydroxides; chrome; phosphorous and brominated flameretardants; antimony trioxide; silica; silicone; and blends thereof.These fillers may particularly include any other fillers and porousfillers and supports known in the art, and may have the modifier of theinvention pre-contacted or pre-absorbed into the filler prior toaddition to the ethylene polymer in one embodiment.

Metal salts of fatty acids may also be present in the polyethylenecompositions of the present invention. Such salts may be present from0.001 wt % to 1 wt % of the composition in one embodiment and from 0.01wt % to 0.8 wt % in another embodiment. Examples of fatty acids includelauric acid, stearic acid, succinic acid, stearyl lactic acid, lacticacid, phthalic acid, benzoic acid, hydroxystearic acid, ricinoleic acid,naphthenic acid, oleic acid, palmitic acid, erucic acid, or anymonocarboxylic aliphatic saturated or unsaturated acid having a chainlength of 7 to 22 carbon atoms. Suitable metals include Li, Na, Mg, Ca,Sr, Ba, Zn, Cd, Al, Sn, Pb, and so forth. Preferably, metal salts offatty acids are magnesium stearate, calcium stearate, sodium stearate,zinc stearate, calcium oleate, zinc oleate, and magnesium oleate.

In a preferred embodiment, slip additives may be present in thecompositions of this invention. Preferably, the slip additives arepresent at 0.001 wt % to 1 wt % (10 ppm to 10,000 ppm), more preferably0.01 wt % to 0.5 wt % (100 ppm to 5000 ppm), more preferably 0.1 wt % to0.3 wt % (1000 ppm to 3000 ppm), based upon the weight of thecomposition. Desirable slip additives include, but are not limited to,saturated fatty acid amides (such as palmitamide, stearamide,arachidamide, behenamide, stearyl stearamide, palmityl pamitamide, andstearyl arachidamide); saturated ethylene-bis-amides (such asstearamido-ethyl-stearamide, stearamido-ethyl-palmitamide, andpalmitamido-ethyl-stearamide); unsaturated fatty acid amides (such asoleamide, erucamide, and linoleamide); unsaturated ethylene-bis-amides(such as ethylene-bis-stearamide, ethylene-bis-oleamide,stearyl-erucamide, erucamido-ethyl-erucamide, oleamido-ethyl-oleamide,erucamido-ethyl-oleamide, oleamido-ethyl-lerucamide,stearamido-ethyl-erucamide, erucamido-ethyl-palmitamide, andpalmitamido-ethyl-oleamide); glycols; polyether polyols (such asCarbowax); acids of aliphatic hydrocarbons (such as adipic acid andsebacic acid); esters of aromatic or aliphatic hydrocarbons (such asglycerol monostearate and pentaerythritol monooleate);styrene-alpha-methyl styrene; fluoro-containing polymers (such aspolytetrafluoroethylene, fluorine oils, and fluorine waxes); siliconcompounds (such as silanes and silicone polymers, including siliconeoils, modified silicones and cured silicones); sodium alkylsulfates;alkyl phosphoric acid esters; and mixtures thereof. Preferred slipadditives are unsaturated fatty acid amides, which are commerciallyavailable from Crompton (Kekamide™ grades), Croda Universal (Crodamide™grades), and Akzo Nobel Amides Co. Ltd. (ARMOSLIP™ grades).Particularly, preferred slip agents include unsaturated fatty acidamides having the chemical structure:CH₃(CH₂)₇CH═CH(CH₂)_(x)CONH₂where x is 5 to 15. Preferred versions include: 1) Erucamide, where x is11, also referred to as cis-13-docosenoamide (commercially available asARMOSLIP E); 2) Oleylamide, where x is 8; and 3) Oleamide, where x is 7,also referred to as N-9-octadecenyl-hexadecanamide. In anotherembodiment, stearamide is also useful in this invention. Other preferredslip additives include those described in WO 2004/005601A1.

In some embodiments, the polyethylene compositions produced by thisinvention may be blended with one or more other polymers, including butnot limited to, thermoplastic polymer(s) and/or elastomer(s).

By “thermoplastic polymer(s)” is meant a polymer that can be melted byheat and then cooled without appreciable change in solid-stateproperties before and after heating. Thermoplastic polymers typicallyinclude, but are not limited to, polyolefins, polyamides, polyesters,polycarbonates, polysulfones, polyacetals, polylactones,acrylonitrile-butadiene-styrene resins, polyphenylene oxide,polyphenylene sulfide, styrene-acrylonitrile resins, styrene maleicanhydride, polyimides, aromatic polyketones, or mixtures of two or moreof the above. Preferred polyolefins include, but are not limited to,polymers comprising one or more linear, branched or cyclic C₂ to C₄₀olefins, preferably polymers comprising ethylene copolymerized with oneor more C₃ to C₄₀ olefins, preferably a C₃ to C₂₀ alpha olefin, morepreferably C₃ to C₁₀ alpha-olefins. A particularly preferred example ispolybutene. The most preferred polyolefin is polypropylene. Otherpreferred polyolefins include, but are not limited to, polymerscomprising ethylene including but not limited to ethylene copolymerizedwith a C₃ to C₄₀ olefin, preferably a C₃ to C₂₀ alpha olefin, morepreferably propylene, butene, hexene, and/or octene.

By “elastomers” is meant all natural and synthetic rubbers, includingthose defined in ASTM D1566. Examples of preferred elastomers include,but are not limited to, ethylene propylene rubber, ethylene propylenediene monomer rubber, styrenic block copolymer rubbers (including SEBS,SI, SIS, SB, SBS, SIBS, and the like, where S=styrene, EB=randomethylene+butene, I=isoprene, and B=butadiene), butyl rubber, halobutylrubber, copolymers of isobutylene and para-alkylstyrene, halogenatedcopolymers of isobutylene and para-alkylstyrene, natural rubber,polyisoprene, copolymers of butadiene with acrylonitrile,polychloroprene, alkyl acrylate rubber, chlorinated isoprene rubber,acrylonitrile chlorinated isoprene rubber, and polybutadiene rubber(both cis and trans).

In another embodiment, the blend comprising the modifier may further becombined with one or more polymers polymerizable by a high-pressure freeradical process, polyvinylchloride, polybutene-1, isotactic polybutene,ABS resins, block copolymer, styrenic block copolymers, polyamides,polycarbonates, PET resins, crosslinked polyethylene, copolymers ofethylene and vinyl alcohol (EVOH), and polymers of aromatic monomerssuch as polystyrene, poly-1 esters, polyacetal, polyvinylidine fluoride,polyethylene glycols, and/or polyisobutylene.

Tackifiers may be blended with the ethylene compositions of thisinvention. Examples of useful tackifiers include, but are not limitedto, aliphatic hydrocarbon resins, aromatic modified aliphatichydrocarbon resins, hydrogenated polycyclopentadiene resins,polycyclopentadiene resins, gum rosins, gum rosin esters, wood rosins,wood rosin esters, tall oil rosins, tall oil rosin esters, polyterpenes,aromatic modified polyterpenes, terpene phenolics, aromatic modifiedhydrogenated polycyclopentadiene resins, hydrogenated aliphatic resin,hydrogenated aliphatic aromatic resins, hydrogenated terpenes andmodified terpenes, and hydrogenated rosin esters. In some embodiments,the tackifier is hydrogenated. In other embodiments the tackifier isnon-polar. (Non-polar is meant that the tackifier is substantially freeof monomers having polar groups. Preferably, the polar groups are notpresent; however, if they are, preferably they are present at not morethan 5 wt %, preferably at not more than 2 wt %, and even morepreferably at not more than 0.5 wt %, based upon the weight of thetackifier.) In some embodiments, the tackifier has a softening point(Ring and Ball, as measured by ASTM E-28) of 80° C. to 140° C.,preferably 100° C. to 130° C. The tackifier, if present, is typicallypresent at about 1 wt % to about 50 wt %, based upon the weight of theblend, more preferably 10 wt % to 40 wt %, and even more preferably 20wt % to 40 wt %. Preferably, however, tackifier is not present, or ifpresent, is present at less than 10 wt %, preferably less than 5 wt %,and more preferably at less than 1 wt %.

Blending and Processing

The compositions and blends described herein may be formed usingconventional equipment and methods, such as by dry blending theindividual components and subsequently melt mixing in a mixer, or bymixing the components together directly in a mixer, such as, forexample, a Banbury mixer, a Haake mixer, a Brabender internal mixer, ora single or twin-screw extruder, which may include a compoundingextruder and a side-arm extruder used directly downstream of apolymerization process. Additionally, additives may be included in theblend, in one or more components of the blend, and/or in a productformed from the blend, such as a film, as desired. Such additives arewell known in the art, and can include, for example: fillers;antioxidants (e.g., hindered phenolics such as IRGANOX™ 1010 or IRGANOX™1076 available from Ciba-Geigy); phosphites (e.g., IRGAFOS™ 168available from Ciba-Geigy); anti-cling additives; tackifiers, such aspolybutenes, terpene resins, aliphatic and aromatic hydrocarbon resins,alkali metal and glycerol stearates, and hydrogenated rosins; UVstabilizers; heat stabilizers; antiblocking agents; release agents;anti-static agents; pigments; colorants; dyes; waxes; silica; fillers;talc; and the like.

The polymers suitable for use in the present invention can be in anyphysical form when used to blend with the modifier of the invention. Inone embodiment, reactor granules, defined as the granules of polymerthat are isolated from the polymerization reactor prior to anyprocessing procedures, are used to blend with the modifier of theinvention. The reactor granules typically have an average diameter offrom 50 μm to 10 mm in one embodiment and from 10 μm to 5 mm in anotherembodiment. In another embodiment, the polymer is in the form ofpellets, such as, for example, having an average diameter of from 1 mmto 10 mm that are formed from melt extrusion of the reactor granules.

The components of the present invention can be blended by any suitablemeans, and are typically blended to yield an intimately mixedcomposition which may be a homogeneous, single phase mixture. Forexample, they may be blended in a static mixer, batch mixer, extruder,or a combination thereof, that is sufficient to achieve an adequatedispersion of modifier in the polymer.

The mixing step may involve first dry blending using, for example, atumble blender, where the polymer and modifier are brought into contactfirst, without intimate mixing, which may then be followed by meltblending in an extruder. Another method of blending the components is tomelt blend the polymer pellets with the modifier directly in an extruderor batch mixer. It may also involve a “master batch” approach, where thefinal modifier concentration is achieved by combining neat polymer withan appropriate amount of modified polymer that had been previouslyprepared at a higher modifier concentration. The mixing step may takeplace as part of a processing method used to fabricate articles, such asin the extruder on an injection molding machine or blown-film line orfiber line.

In a preferred aspect of the invention, the ethylene polymer andmodifier are “melt blended” in an apparatus such as an extruder (singleor twin screw) or batch mixer. The ethylene polymer may also be “dryblended” with the modifier using a tumbler, double-cone blender, ribbonblender, or other suitable blender. In yet another embodiment, theethylene polymer and modifier are blended by a combination ofapproaches, for example, a tumbler followed by an extruder. A preferredmethod of blending is to include the final stage of blending as part ofan article fabrication step, such as in the extruder used to melt andconvey the composition for a molding step like injection molding or blowmolding. This could include direct injection of the modifier into theextruder, either before or after the polyethylene is fully melted.Extrusion technology for polyethylene is described in more detail in,for example, PLASTICS EXTRUSION TECHNOLOGY 26-37 (Friedhelm Hensen, ed.Hanser Publishers 1988).

In another aspect of the invention, the polyethylene composition may beblended in solution by any suitable means, by using a solvent thatdissolves both components to a significant extent. The blending mayoccur at any temperature or pressure where the modifier and the ethylenepolymer remain in solution. Preferred conditions include blending athigh temperatures, such as 10° C. or more, preferably 20° C. or moreover the melting point of the ethylene polymer. Such solution blendingwould be particularly useful in processes where the ethylene polymer ismade by solution process and the modifier is added directly to thefinishing train, rather than added to the dry polymer in anotherblending step altogether. Such solution blending would also beparticularly useful in processes where the ethylene polymer is made in abulk or high pressure process where both the polymer and the modifierwere soluble in the monomer. As with the solution process the modifieris added directly to the finishing train, rather than added to the drypolymer in another blending step altogether.

Thus, in the cases of fabrication of articles using methods that involvean extruder, such as injection molding or blow molding, any means ofcombining the polyethylene and modifier to achieve the desiredcomposition serve equally well as fully formulated pre-blended pellets,since the forming process includes a re-melting and mixing of the rawmaterial; example combinations include simple blends of neat polymerpellets and modifier, of neat polymer granules and modifier, of neatpolymer pellets and pre-blended pellets, and of neat polymer granulesand pre-blended pellets. Here, “pre-blended pellets” means pellets of apolyethylene composition comprising ethylene polymer and modifier atsome concentration. In the process of compression molding, however,little mixing of the melt components occurs and pre-blended pelletswould be preferred over simple blends of the constituent pellets (orgranules) and modifier. Those skilled in the art will be able todetermine the appropriate procedure for blending of the polymers tobalance the need for intimate mixing of the component ingredients withthe desire for process economy.

Applications

The enhanced properties of the polyethylene compositions describedherein are useful in a wide variety of applications, includingtransparent articles, such as cook and storage ware, and in otherarticles, such as furniture, automotive components, toys, sportswear,medical devices, sterilizable medical devices and sterilizationcontainers, nonwoven fibers and fabrics and articles therefrom, such asdrapes, gowns, filters, hygiene products, diapers, and films, orientedfilms, sheets, tubes, pipes and other items where softness, high impactstrength, and impact strength below freezing is important.

Additional examples of desirable articles of manufacture made fromcompositions of the invention include films, sheets, fibers, woven andnonwoven fabrics, automotive components, furniture, sporting equipment,food storage containers, transparent and semi-transparent articles,toys, tubing and pipes, sheets, packaging, bags, sacks, coatings, caps,closures, crates, pallets, cups, non-food containers, pails, insulation,and medical devices. Further examples include automotive components,wire and cable jacketing, pipes, agricultural films, geomembranes, toys,sporting equipment, medical devices, casting and blowing of packagingfilms, extrusion of tubing, pipes and profiles, sporting equipment,outdoor furniture (e.g., garden furniture) and playground equipment,boat and water craft components, and other such articles. In particular,the compositions are suitable for automotive components such as bumpers,grills, trim parts, dashboards and instrument panels, exterior door andhood components, spoiler, wind screen, hub caps, mirror housing, bodypanel, protective side molding, and other interior and externalcomponents associated with automobiles, trucks, boats, and othervehicles.

Other useful articles and goods may be formed economically by thepractice of our invention including: crates, containers, packaging,labware, such as roller bottles for culture growth and media bottles,office floor mats, instrumentation sample holders and sample windows;liquid storage containers such as bags, pouches, and bottles for storageand IV infusion of blood or solutions; packaging material includingthose for any medical device or drugs including unit-dose or otherblister or bubble pack, as well as for wrapping or containing foodpreserved by irradiation. Other useful items include medical tubing andvalves for any medical device including infusion kits, catheters, andrespiratory therapy, as well as packaging materials for medical devicesor food which is irradiated including trays, as well as stored liquid,particularly water, milk, or juice, containers including unit servingsand bulk storage containers, as well as transfer means such as tubing,pipes, and such.

Fabrication of these articles may be accomplished by injection molding,extrusion, thermoforming, blow molding, rotational molding(rotomolding), fiber spinning, spin bonding or melt blown bonding suchas for non-woven fabrics, film blowing, stretching for oriented films,casting such as for films (including use of chill rolls), profiledeformation, coating (film, wire, and cable), compression molding,calendering, foaming, laminating, transfer molding, cast molding,pultrusion, protrusion, draw reduction, and other common processingmethods, or combinations thereof, such as is known in the art anddescribed in, for example, PLASTICS PROCESSING (Radian Corporation,Noyes Data Corp. 1986). Use of at least thermoforming or filmapplications allows for the possibility of and derivation of benefitsfrom uniaxial or biaxial orientation. Sufficient mixing should takeplace to assure that an intimately mixed, preferably uniform, blend willbe produced prior to conversion into a finished product.

Adhesives

The polymers of this invention or blends thereof can be used asadhesives, either alone or combined with tackifiers. Preferredtackifiers are described above. The tackifier is typically present atabout 1 wt % to about 50 wt %, based upon the weight of the blend, morepreferably 10 wt % to 40 wt %, even more preferably 20 wt % to 40 wt %.Other additives, as described above, may be added also.

The adhesives of this invention can be used in any adhesive applicationincluding, but not limited to, disposables, packaging, laminates,pressure sensitive adhesives, tapes labels, wood binding, paper binding,non-wovens, road marking, reflective coatings, and the like. In apreferred embodiment, the adhesives of this invention can be used fordisposable diaper and napkin chassis construction, elastic attachment indisposable goods converting, packaging, labeling, bookbinding,woodworking, and other assembly applications. Particularly, preferredapplications include: baby diaper leg elastic, diaper frontal tape,diaper standing leg cuff, diaper chassis construction, diaper corestabilization, diaper liquid transfer layer, diaper outer coverlamination, diaper elastic cuff lamination, feminine napkin corestabilization, feminine napkin adhesive strip, industrial filtrationbonding, industrial filter material lamination, filter mask lamination,surgical gown lamination, surgical drape lamination, and perishableproducts packaging.

Films

The compositions described above and the blends thereof may be formedinto monolayer or multilayer films. These films may be formed by any ofthe conventional techniques known in the art including extrusion,co-extrusion, extrusion coating, lamination, blowing, and casting. Thefilm may be obtained by the flat film or tubular process which may befollowed by orientation in a uniaxial direction or in two mutuallyperpendicular directions in the plane of the film. One or more of thelayers of the film may be oriented in the transverse and/or longitudinaldirections to the same or different extents. This orientation may occurbefore or after the individual layers are brought together. For example,a polyethylene layer can be extrusion coated or laminated onto anoriented polypropylene layer or the polyethylene and polypropylene canbe coextruded together into a film then oriented. Likewise, orientedpolypropylene could be laminated to oriented polyethylene or orientedpolyethylene could be coated onto polypropylene then optionally thecombination could be oriented even further. Typically the films areoriented in the Machine Direction (MD) at a ratio of up to 15,preferably between 5 and 7, and in the Transverse Direction (TD) at aratio of up to 15, preferably 7 to 9. However, in another embodiment,the film is oriented to the same extent in both the MD and TDdirections.

In multilayer constructions, the other layer(s) may be any layertypically included in multilayer film structures. For example, the otherlayer or layers may be:

1. Polyolefins.

Preferred polyolefins include homopolymers or copolymers of C₂ to C₄₀olefins, preferably C₂ to C₂₀ olefins, preferably a copolymer of analpha-olefin and another olefin or alpha-olefin (ethylene is defined tobe an alpha-olefin for purposes of this invention). Preferably,homopolyethylene, homopolypropylene, propylene copolymerized withethylene and/or butene, ethylene copolymerized with one or more ofpropylene, butene or hexene, and optional dienes. Preferred examplesinclude thermoplastic polymers such as ultra low density polyethylene,very low density polyethylene, linear low density polyethylene, lowdensity polyethylene, medium density polyethylene, high densitypolyethylene, polypropylene, isotactic polypropylene, highly isotacticpolypropylene, syndiotactic polypropylene, random copolymer of propyleneand ethylene and/or butene and/or hexene, elastomers such as ethylenepropylene rubber, ethylene propylene diene monomer rubber, neoprene, andblends of thermoplastic polymers and elastomers, such as, for example,thermoplastic elastomers and rubber toughened plastics.

2. Polar Polymers.

Preferred polar polymers include homopolymers and copolymers of esters,amides, acetates, anhydrides, copolymers of a C₂ to C₂₀ olefin, such asethylene, and/or propylene, and/or butene with one or more polarmonomers such as acetates, anhydrides, esters, alcohol, and/or acrylics.Preferred examples include polyesters, polyamides, ethylene vinylacetate copolymers, and polyvinyl chloride.

3. Cationic Polymers.

Preferred cationic polymers include polymers or copolymers of geminallydisubstituted olefins, alpha-heteroatom olefins, and/or styrenicmonomers. Preferred geminally disubstituted olefins include isobutylene,isopentene, isoheptene, isohexane, isooctene, isodecene, andisododecene. Preferred alpha-heteroatom olefins include vinyl ether andvinyl carbazole, preferred styrenic monomers include styrene, alkylstyrene, para-alkyl styrene, alpha-methyl styrene, chloro-styrene, andbromo-para-methyl styrene. Preferred examples of cationic polymersinclude butyl rubber, isobutylene copolymerized with para methylstyrene, polystyrene, and poly-alpha-methyl styrene.

4. Miscellaneous.

Other preferred layers can be paper, wood, cardboard, metal, metal foils(such as aluminum foil and tin foil), metallized surfaces, glass(including silicon oxide (SiO_(X)) coatings applied by evaporatingsilicon oxide onto a film surface), fabric, spunbonded fibers, andnon-wovens (particularly, polypropylene spunbonded fibers ornon-wovens), and substrates coated with inks, dyes, pigments, and thelike.

The films may vary in thickness depending on the intended application;however, films of a thickness from 1 μm to 250 μm are usually suitable.Films intended for packaging are usually from 10 to 60 micron thick. Thethickness of the sealing layer is typically 0.2 μm to 50 μm. There maybe a sealing layer on both the inner and outer surfaces of the film orthe sealing layer may be present on only the inner or the outer surface.

Additives such as block, antiblock, antioxidants, pigments, fillers,processing aids, UV stabilizers, neutralizers, lubricants, surfactants,and/or nucleating agents may also be present in one or more than onelayer in the films. Preferred additives include silicon dioxide,titanium dioxide, polydimethylsiloxane, talc, dyes, wax, calciumsterate, carbon black, low molecular weight resins, and glass beads,preferably, these additives are present at from 0.1 ppm to 1000 ppm.

In another embodiment, one more layers may be modified by coronatreatment, electron beam irradiation, gamma irradiation, or microwaveirradiation. In a preferred embodiment, one or both of the surfacelayers is modified by corona treatment.

The films described herein may also comprise from 5 wt % to 60 wt %,based upon the weight of the polymer and the resin, of a hydrocarbonresin. The resin may be combined with the polymer of the seal layer(s)or may be combined with the polymer in the core layer(s). The resinpreferably has a softening point above 100° C., even more preferablyfrom 130° C. to 180° C. Preferred hydrocarbon resins include thosedescribed above. The films comprising a hydrocarbon resin may beoriented in uniaxial or biaxial directions to the same or differentdegrees. For more information on blends of tackifiers and modifiersuseful herein, see U.S. Ser. No. 60/617,594, filed Oct. 8, 2004.

The films described above may be used as stretch and/or cling films.Stretch/cling films are used in various bundling, packaging, andpalletizing operations. To impart cling properties to, or improve thecling properties of, a particular film, a number of well-knowntackifying additives have been utilized. Common tackifying additivesinclude polybutenes, terpene resins, alkali metal stearates andhydrogenated rosins, and rosin esters. The cling properties of a filmcan also be modified by the well-known physical process referred to ascorona discharge. Some polymers (such as ethylene methyl acrylatecopolymers) do not need cling additives and can be used as cling layerswithout tackifiers. Stretch/clings films may comprise a slip layercomprising any suitable polyolefin or combination of polyolefins such aspolyethylene, polypropylene, copolymers of ethylene and propylene, andpolymers obtained from ethylene and/or propylene copolymerized withminor amounts of other olefins, particularly C₄ to C₁₂ olefins.Particularly, preferred is linear low density polyethylene (LLDPE).Additionally, the slip layer may include one or more anticling (slipand/or antiblock) additives which may be added during the production ofthe polyolefin or subsequently blended in to improve the slip propertiesof this layer. Such additives are well-known in the art and include, forexample, silicas, silicates, diatomaceous earths, talcs, and variouslubricants. These additives are preferably utilized in amounts rangingfrom about 100 ppm to about 20,000 ppm, more preferably between about500 ppm to about 10,000 ppm, by weight based upon the weight of the sliplayer. The slip layer may, if desired, also include one or more otheradditives as described above.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% lower thanthat of a film of the same thickness and of the same composition, absentthe modifier, prepared under the same conditions and a dart impactstrength that is within 20% of a film of the same thickness and of thesame composition, absent the modifier, prepared under the sameconditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% lower thanthat of a film of the same thickness and of the same composition, absentthe modifier, prepared under the same conditions and a MD Tear strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a haze that is at least 10% lower than that of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a dart impact strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a haze that is at least 10% lower than that of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a MD Tear strength thatis within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a haze of 10% or less.

In another embodiment of the invention, films comprising blendsdescribed herein have a haze that is at least 10% less than the hazemeasured on a film of the same thickness and of the same composition,absent the dendritic hydrocarbon polymer modifier, prepared under thesame conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a dart impact strength that is greater than orwithin 30% less than the dart impact strength measured on a film of thesame thickness and of the same composition, absent the dendritichydrocarbon polymer modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have an MD Tear strength that is greater than or within30% less than the MD Tear strength measured on a film of the samethickness and of the same composition, absent the dendritic hydrocarbonpolymer modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions, and the film has a Dart Drop, ing/mil, that is within 30% of the Dart Drop measured on a film of thesame thickness and of the same composition, absent the dendritichydrocarbon polymer modifier, prepared under the same conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions, and the film has an MD Tear strengththat is greater than or within 30% less than the MD Tear strengthmeasured on a film of the same thickness and of the same composition,absent the dendritic hydrocarbon polymer modifier, prepared under thesame conditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a strain hardening ratio that is at least 10%greater than the strain hardening ratio measured on a composition,absent the dendritic hydrocarbon polymer modifier, and the film has aDart Drop, in g/mil, that is within 30% of the Dart Drop measured on afilm of the same thickness and of the same composition, absent thedendritic hydrocarbon polymer modifier, prepared under the sameconditions.

In another embodiment of the invention, films comprising blendsdescribed herein have a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions, and the film has a haze that is atleast 10% less than haze measured on a film of the same thickness and ofthe same composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions.

In a preferred embodiment, films prepared from the compositionsdescribed herein have improved bubble stability compared to the ethylenecopolymers of the compositions alone as determined by reduced gaugevariation, e.g., a gauge variation of 10% or less, preferably 8% orless, preferably 5% or less.

In a preferred embodiment, films prepared from the compositionsdescribed herein have excellent optical properties, such as a haze (ASTMD1003) of 20 or less, preferably 15 or less, preferably 10 or less.

In a preferred embodiment, films, preferably blown films, prepared fromthe blends described herein have one or more of the followingproperties:

a) 1% Secant Modulus (MD) of greater than 25,000 psi, preferably greaterthan 27,000; and/or

b) 1% Secant Modulus (TD) of greater than 25,000 psi, preferably greaterthan 25,000 psi; and/or

c) Tensile Strength at Yield (MD) of greater than 1200 psi, preferablygreater than 1300 psi; and/or

d) Tensile Strength at Yield (TD) of greater than 1200 psi, preferablygreater than 1400 psi; and/or

e) Elongation at Yield (MD) of 6% or more, preferably 7% or more; and/or

f) Elongation at Yield (TD) of 5% or more, preferably, 6% or more,preferably 7% or more; and/or

g) Tensile Strength (MD) of 7000 psi or more, preferably 7500 psi ormore; and/or

h) Tensile Strength (TD) of 7000 psi or more, preferably 7500 psi ormore; and/or

i) Elongation at Break (MD) 650% or more, preferably 680% or more;and/or

j) Elongation at Break (TD) 630% or more, preferably 650% or more,preferably 680% or more; and/or

k) Elmendorf Tear (MD) of at least 400 g; and/or

l) Elmendorf Tear (TD) of at least 500 g; and/or

m) Elmendorf Tear (MD) of at least 300 g/mil, preferably at least 325g/mil; and/or

n) Elmendorf Tear (TD) of at least 400 g/mil, preferably at least 410g/mil; and/or

o) Dart Drop of at least 300 g, preferably at least 350 g; and/or

p) Dart Drop of at least 200 g/mil, preferably at least 250 g/mil,preferably at least 300 g/mil; and/or

q) Haze of less than 15%, preferably less than 10%, preferably less than7%, preferably less than 6%; and/or

r) Internal Haze of less than 2%, preferably less than 1.5%; and/or

s) Gauge COV of less than 12%, preferably less than 11%, preferably lessthan 10%, preferably less than 9%; and/or

t) 5 wt % or less (preferably 4 wt % or less, preferably 3 wt % or less)of xylene insoluble material.

In a preferred embodiment, the films described herein, preferably theblown films, have at least two of the above properties in anycombination whatsoever, preferably at least three of the aboveproperties in any combination whatsoever, preferably at least four ofthe above properties in any combination whatsoever, preferably at leastfive of the above properties in any combination whatsoever, preferablyat least six of the above properties in any combination whatsoever,preferably at least seven of the above properties in any combinationwhatsoever, preferably at least eight of the above properties in anycombination whatsoever, preferably at least nine of the above propertiesin any combination whatsoever, preferably at least ten of the aboveproperties in any combination whatsoever, preferably at least eleven ofthe above properties in any combination whatsoever, preferably at leasttwelve of the above properties in any combination whatsoever, preferablyat least thirteen of the above properties in any combination whatsoever,preferably at least fourteen of the above properties in any combinationwhatsoever, preferably at least fifteen of the above properties in anycombination whatsoever, preferably at least sixteen of the aboveproperties in any combination whatsoever, preferably at least seventeenof the above properties in any combination whatsoever, preferably atleast eighteen of the above properties in any combination whatsoever,preferably at least nineteen of the above properties in any combinationwhatsoever, preferably all twenty of the above properties.

In a preferred embodiment, the blown film has a total haze of 10% orless, a 1% (MD) Secant Modulus of 25,000 psi or more, an MD Tear of 300g or more, and a Dart Drop of 200 or more g/mil, and TD 1% SecantModulus of 25,000 psi or more.

In a preferred embodiment, the blown film has a total haze of 10% orless, a Gauge COV of less than 12%, a 1% (MD) Secant Modulus of 25,000psi or more, an MD Tear of 300 g or more, and a Dart Drop of 200 or moreg/mil.

Molded and Extruded Products

The polyethylene composition described above may also be used to preparemolded products in any molding process including, but not limited to,injection molding, gas-assisted injection molding, extrusion blowmolding, injection blow molding, injection stretch blow molding,compression molding, rotational molding, foam molding, thermoforming,sheet extrusion, and profile extrusion. The molding processes are wellknown to those of ordinary skill in the art.

The compositions described herein may be shaped into desirable end usearticles by any suitable means known in the art. Thermoforming, vacuumforming, blow molding, rotational molding, slush molding, transfermolding, wet lay-up or contact molding, cast molding, cold formingmatched-die molding, injection molding, spray techniques, profileco-extrusion, or combinations thereof are typically used methods.

Thermoforming is a process of forming at least one pliable plastic sheetinto a desired shape. An embodiment of a thermoforming sequence isdescribed; however, this should not be construed as limiting thethermoforming methods useful with the compositions of this invention.First, an extrudate film of the composition of this invention (and anyother layers or materials) is placed on a shuttle rack to hold it duringheating. The shuttle rack indexes into the oven which pre-heats the filmbefore forming Once the film is heated, the shuttle rack indexes back tothe forming tool. The film is then vacuumed onto the forming tool tohold it in place and the forming tool is closed. The forming tool can beeither “male” or “female” type tools. The tool stays closed to cool thefilm and the tool is then opened. The shaped laminate is then removedfrom the tool. Thermoforming is accomplished by vacuum, positive airpressure, plug-assisted vacuum forming, or combinations and variationsof these, once the sheet of material reaches thermoforming temperatures,typically of from 140° C. to 185° C. or higher. A pre-stretched bubblestep is used, especially on large parts, to improve materialdistribution. In one embodiment, an articulating rack lifts the heatedlaminate towards a male forming tool, assisted by the application of avacuum from orifices in the male forming tool. Once the laminate isfirmly formed about the male forming tool, the thermoformed shapedlaminate is then cooled, typically by blowers. Plug-assisted forming isgenerally used for small, deep drawn parts. Plug material, design, andtiming can be critical to optimization of the process. Plugs made frominsulating foam avoid premature quenching of the plastic. The plug shapeis usually similar to the mold cavity, but smaller and without partdetail. A round plug bottom will usually promote even materialdistribution and uniform side-wall thickness. For a semicrystallinepolymer, fast plug speeds generally provide the best materialdistribution in the part. The shaped laminate is then cooled in themold. Sufficient cooling to maintain a mold temperature of 30° C. to 65°C. is desirable. The part is below 90° C. to 100° C. before ejection inone embodiment. The shaped laminate is then trimmed of excess laminatematerial.

Blow molding is another suitable forming means, which includes injectionblow molding, multi-layer blow molding, extrusion blow molding, andstretch blow molding, and is especially suitable for substantiallyclosed or hollow objects, such as, for example, gas tanks and otherfluid containers. Blow molding is described in more detail in, forexample, CONCISE ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING(Jacqueline I. Kroschwitz, ed., John Wiley & Sons 1990).

In yet another embodiment of the formation and shaping process, profileco-extrusion can be used. The profile co-extrusion process parametersare as above for the blow molding process, except the die temperatures(dual zone top and bottom) range from 150° C. to 235° C., the feedblocks are from 90° C. to 250° C., and the water cooling tanktemperatures are from 10° C. to 40° C.

One embodiment of an injection molding process is described as follows.The shaped laminate is placed into the injection molding tool. The moldis closed and the substrate material is injected into the mold. Thesubstrate material has a melt temperature between 180° C. and 300° C. inone embodiment, from 200° C. and 250° C. in another embodiment, and isinjected into the mold at an injection speed of between 2 and 10seconds. After injection, the material is packed or held at apredetermined time and pressure to make the part dimensionally andaesthetically correct. Typical time periods are from 5 to 25 seconds andpressures from 1,000 kPa to 15,000 kPa. The mold is cooled between 10°C. and 70° C. to cool the substrate. The temperature will depend on thedesired gloss and appearance desired. Typical cooling time is from 10 to30 seconds, depending on part on the thickness. Finally, the mold isopened and the shaped composite article ejected.

Likewise, molded articles may be fabricated by injecting molten polymerblend into a mold that shapes and solidifies the molten polymer intodesirable geometry and thickness of molded articles. A sheet may be madeeither by extruding a substantially flat profile from a die, onto achill roll, or alternatively by calendering. Sheets will generally beconsidered to have a thickness of from 10 mils to 100 mils (254 μm to2540 μm), although sheets may be substantially thicker. Tubing or pipemay be obtained by profile extrusion for uses in medical, potable water,land drainage applications, or the like. The profile extrusion processinvolves the extrusion of molten polymer through a die. The extrudedtubing or pipe is then solidified by chill water or cooling air into acontinuous extruded articles. The tubing will generally be in the rangeof from 0.31 cm to 2.54 cm in outside diameter and have a wall thicknessof in the range of from 254 μm to 0.5 cm. The pipe will generally be inthe range of from 2.54 cm to 254 cm in outside diameter and have a wallthickness of in the range of from 0.5 cm to 15 cm. Sheets made from theproducts of an embodiment of a version of the present invention may beused to form containers. Such containers may be formed by thermoforming,solid phase pressure forming, stamping, and other shaping techniques.Sheets may also be formed to cover floors or walls or other surfaces.

In an embodiment of the thermoforming process, the oven temperature isbetween 160° C. and 195° C., the time in the oven between 10 and 20seconds, and the die temperature, typically a male die, between 10° C.and 71° C. The final thickness of the cooled (room temperature), shapedlaminate is from 10 μm to 6000 μm in one embodiment, from 200 μm to 6000μm in another embodiment, from 250 μm to 3000 μm in yet anotherembodiment, and from 500 μm to 1550 μm in yet another embodiment, adesirable range being any combination of any upper thickness limit withany lower thickness limit.

In an embodiment of the injection molding process, wherein a substratematerial is injection molded into a tool including the shaped laminate,the melt temperature of the substrate material is between 190° C. and255° C. in one embodiment and between 210° C. and 250° C. in anotherembodiment; the fill time from 2 to 10 seconds in one embodiment andfrom 2 to 8 seconds in another embodiment; and a tool temperature offrom 25° C. to 65° C. in one embodiment and from 27° C. and 60° C. inanother embodiment. In a desirable embodiment, the substrate material isat a temperature that is hot enough to melt any tie-layer material orbacking layer to achieve adhesion between the layers.

In yet another embodiment of the invention, the compositions of thisinvention may be secured to a substrate material using a blow moldingoperation. Blow molding is particularly useful in such applications asfor making closed articles such as fuel tanks and other fluidcontainers, playground equipment, outdoor furniture, and small enclosedstructures.

It will be understood by those skilled in the art that the stepsoutlined above may be varied, depending upon the desired result. Forexample, the extruded sheet of the compositions of this invention may bedirectly thermoformed or blow molded without cooling, thus skipping acooling step. Other parameters may be varied as well in order to achievea finished composite article having desirable features.

In another embodiment, this invention relates to:

1. A polyethylene blend comprising one or more ethylene polymers and oneor more dendritic hydrocarbon polymer modifiers, wherein the modifierhas: 1) a g′_(vis) value less than 0.75; 2) at least 0.6 ppm estergroups as determined by ¹H NMR; 3) a Tm of 100° C. or more; 4) an Mw of50,000 g/mol or more, as determined by GPC; and 5) an average number ofcarbon atoms between branch points of 70 or more as determined by ¹HNMR.2. The composition of paragraph 1, wherein the modifier has 5 wt % orless of xylene insoluble material.3. The composition of paragraph 1 or 2, wherein the modifier has aweight average molecular weight between the branch points of 1,000 g/molor more.4. The composition of paragraph 1, 2, or 3, wherein the modifier ispresent at 0.25 wt % to 10 wt %, based upon the weight of the blend.5. The composition of any of paragraphs 1 to 4, wherein the polyethylenecomprises a copolymer of ethylene and one or more C₃ to C₂₀ alphaolefinsand has an M_(w) of 20,000 to 1,000,000 g/mol.6. The composition of any of paragraphs 1 to 5, wherein the polyethylenehas a density of 0.91 to 0.96 g/cm³.7. The composition of any of paragraphs 1 to 6, wherein the modifier ispresent at from 0.1 wt % to 5 wt % (based upon the weight of the blend);the polyethylene has a composition distribution breadth index of 60% ormore and a density of 0.90 g/cc or more.8. The modifier of any of paragraphs 1 to 7, wherein the modifier has astrain-hardening ratio of 2 or more and the blend has a strain hardeningratio of greater than 1.0.9. A polyethylene film comprising the blend of any of paragraphs 1 to 8,said film having a gauge variation that is at least 10% lower than thatof a film of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a dart impact strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.10. A polyethylene film comprising the blend of any of paragraphs 1 to9, said film having a gauge variation that is at least 10% lower thanthat of a film of the same thickness and of the same composition, absentthe modifier, prepared under the same conditions and a MD Tear strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.11. A polyethylene film comprising the blend of any of paragraphs 1 to10, said film having a haze that is at least 10% lower than that of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a dart impact strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.12. A polyethylene film comprising the blend of any of paragraphs 1 to11, said film having a haze that is at least 10% lower than that of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a MD Tear strength thatis within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.13. A film comprising the composition of any of paragraphs 1 to 12, saidfilm having a haze of 10% or less.14. A film comprising the composition of any of paragraphs 1 to 13,wherein the film has a haze that is at least 10% less than the hazemeasured on a film of the same thickness and of the same composition,absent the dendritic hydrocarbon polymer modifier, prepared under thesame conditions.15. A film comprising the composition of any of paragraphs 1 to 14,wherein the film has a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions.16. A film comprising the composition of any of paragraphs 1 to 15,wherein the film has a dart impact strength that is greater than orwithin 30% less than the dart impact strength measured on a film of thesame thickness and of the same composition, absent the dendritichydrocarbon polymer modifier, prepared under the same conditions.17. A film comprising the composition of any of paragraphs 1 to 16,wherein the film has an MD Tear strength that is greater than or within30% less than the MD Tear strength measured on a film of the samethickness and of the same composition, absent the dendritic hydrocarbonpolymer modifier, prepared under the same conditions.18. A film comprising the blend of any of paragraphs 1 to 17, whereinthe film has a gauge variation that is at least 10% less than the gaugevariation measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions, and the film has a Dart Drop, in g/mil, thatwithin 30% of the Dart Drop measured on a film of the same thickness andof the same composition, absent the dendritic hydrocarbon polymermodifier, prepared under the same conditions.19. A film comprising the blend of any of paragraphs 1 to 18, whereinthe film has a gauge variation that is at least 10% less than the gaugevariation measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions, and the film has an MD Tear strength that isgreater than or within 30% less than the MD Tear strength measured on afilm of the same thickness and of the same composition, absent thedendritic hydrocarbon polymer modifier, prepared under the sameconditions.20. A film comprising the blend of any of paragraphs 1 to 19, whereinthe blend composition has a strain hardening ratio that is at least 10%greater than the strain hardening ratio measured on a composition,absent the dendritic hydrocarbon polymer modifier, and the film has aDart Drop, in g/mil, that within 30% of the Dart Drop measured on a filmof the same thickness and of the same composition, absent the dendritichydrocarbon polymer modifier, prepared under the same conditions.21. A film comprising the blend of any of paragraphs 1 to 20, whereinthe film has a gauge variation that is at least 10% less than the gaugevariation measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions, and the film has a haze that is at least 10%less than haze measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions.22. The composition of any of paragraphs 1 to 21 comprising more than 25wt % (based on the weight of the composition) of one or more ethylenepolymers having a g′_(vis) of 0.95 or more and an M_(w) of 20,000 g/molor more and at least 0.1 wt % of a dendritic hydrocarbon polymermodifier where the modifier has a g′_(vis) of less than 0.75, whereinthe ethylene polymer has a g′_(vis) of at least 0.25 units higher thanthe g′_(vis) of the branched modifier.23. The composition of any of paragraphs 1 to 22, wherein the modifierhas a shear thinning ratio of complex viscosity at a frequency of 0.01rad/sec to the complex viscosity at a frequency of 398 rad/sec greaterthan 53.9*I2^((−0.74)), where I2 is the melt index according to ASTM1238 D, 190° C., 2.16 kg.Test Methods

Melt Index (MI, also referred to as I2) is measured according to ASTMD1238 at 190° C., under a load of 2.16 kg unless otherwise noted. Theunits for MI are g/10 min or dg/min.

High Load Melt Index (HLMI, also referred to as I21) is the melt flowrate measured according to ASTM D-1238 at 190° C., under a load of 21.6kg. The units for HLMI are g/10 min or dg/min.

Melt Index Ratio (MIR) is the ratio of the high load melt index to themelt index, or I21/I2.

Density is measured by density-gradient column, as described in ASTMD1505, on a compression-molded specimen that has been slowly cooled toroom temperature (i.e., over a period of 10 minutes or more) and allowedto age for a sufficient time that the density is constant within+/−0.001 g/cm³. The units for density are g/cm³.

Gauge, reported in mils, was measured using a Measuretech Series 200instrument. The instrument measures film thickness using a capacitancegauge. For each film sample, ten film thickness data points weremeasured per inch of film as the film was passed through the gauge in atransverse direction. From these measurements, an average gaugemeasurement was determined and reported. Coefficient of variation (GaugeCOV) is used to measure the variation of film thickness in thetransverse direction. The Gauge COV is defined as a ratio of thestandard deviation to the mean of film thickness. Elmendorf Tear,reported in grams (g) or grams per mil (g/mil), was measured asspecified by ASTM D-1922.

Tensile Strength at Yield, Tensile Strength at Break, Ultimate TensileStrength and Tensile Strength at 50%, 100%, and/or 200% Elongation weremeasured as specified by ASTM D-882.

Tensile Peak Load was measured as specified by ASTM D-882.

Tensile Energy, reported in inch-pounds (in-lb), was measured asspecified by ASTM D-882.

Elongation at Yield and Elongation at Break, reported as a percentage(%), were measured as specified by ASTM D-882.

1% Secant Modulus (M), reported in pounds per square inch (lb/in² orpsi), was measured as specified by ASTM D-882.

Haze, reported as a percentage (%), was measured as specified by ASTMD-1003. Internal Haze, reported as a percentage (%), is the hazeexcluding any film surface contribution. The film surfaces are coatedwith ASTM approved inert liquids to eliminate any haze contribution fromthe film surface topology. The internal haze measurement procedure isper ASTM D 1003. Unless otherwise indicated the haze value reported istotal haze.

Gloss, a dimensionless number, was measured as specified by ASTM D-2457at 45 degrees.

Dart Drop Impact or Dart Drop Impact Strength (DIS), reported in grams(g) and/or grams per mil (g/mil), was measured as specified by ASTMD-1709, method A, unless otherwise specified.

“Melt strength” is defined as the force required to draw a moltenpolymer extrudate at a rate of 12 mm/s² and at an extrusion temperatureof 190° C. until breakage of the extrudate whereby the force is appliedby take up rollers. The polymer is extruded at a velocity of 0.33 mm/sthrough an annular die of 2 mm diameter and 30 mm length. Melt strengthvalues reported herein are determined using a Gottfert Rheotens testerand are reported in centi-Newtons (cN). Additional experimentalparameters for determining the melt strength are listed in Table 1. Forthe measurements of melt strength, the resins were stabilized with 500ppm of Irganox 1076 and 1500 ppm of Irgafos 168.

TABLE 1 Melt Strength test parameters Acceleration 12 mm/s² Temperature190° C. Piston diameter 12 mm Piston speed 0.178 mm/s Die diameter 2 mmDie length 30 mm Shear rate at the die 40.05 s⁻¹ Strand length 100.0 mmVo (velocity at die exit) 10.0 mm/s

Dynamic shear melt rheological data was measured with an AdvancedRheometrics Expansion System (ARES) using parallel plates (diameter=25mm) in a dynamic mode under nitrogen atmosphere. For all experiments,the rheometer was thermally stable at 190° C. for at least 30 minutesbefore inserting compression-molded sample of resin onto the parallelplates. To determine the samples viscoelastic behavior, frequency sweepsin the range from 0.01 to 385 rad/s were carried out at 190° C. underconstant strain. Depending on the molecular weight and temperature,strains of 10% and 15% were used and linearity of the response wasverified. A nitrogen stream was circulated through the sample oven tominimize chain extension or cross-linking during the experiments. Allthe samples were compression molded at 190° C. and no stabilizers wereadded. A sinusoidal shear strain is applied to the material if thestrain amplitude is sufficiently small the material behaves linearly. Itcan be shown that the resulting steady-state stress will also oscillatesinusoidally at the same frequency but will be shifted by a phase angleδ with respect to the strain wave. The stress leads the strain by δ. Forpurely elastic materials δ=0° (stress is in phase with strain) and forpurely viscous materials, δ=90° (stress leads the strain by 90° althoughthe stress is in phase with the strain rate). For viscoelasticmaterials, 0<δ<90. The shear thinning slope (STS) was measured usingplots of the logarithm (base ten) of the dynamic viscosity versuslogarithm (base ten) of the frequency. The slope is the difference inthe log (dynamic viscosity) at a frequency of 100 s⁻¹ and the log(dynamic viscosity) at a frequency of 0.01 s⁻¹ divided by 4.

The complex shear viscosity (η*) versus frequency (ω) curves were fittedusing the Cross model (see, for example, C. W. Macosco, RHEOLOGY:PRINCIPLES, MEASUREMENTS, AND APPLICATIONS, Wiley-VCH, 1994):

$\eta^{*} = {\frac{\eta_{0}}{1 + \left( {\lambda\;\omega} \right)^{1 - n}}.}$The three parameters in this model are: η₀, the zero-shear viscosity; λ,the average relaxation time; and n, the power-law exponent. Thezero-shear viscosity is the value at a plateau in the Newtonian regionof the flow curve at a low frequency, where the dynamic viscosity isindependent of frequency. The average relaxation time corresponds to theinverse of the frequency at which shear-thinning starts. The power-lawexponent describes the extent of shear-thinning, in that the magnitudeof the slope of the flow curve at high frequencies approaches 1−n on alog(η*)-log(ω) plot. For Newtonian fluids, n=1 and the dynamic complexviscosity is independent of frequency. For the polymers of interesthere, n<1, so that enhanced shear-thinning behavior is indicated by adecrease in n (increase in 1−n).

The transient uniaxial extensional viscosity was measured using aSER-2-A Testing Platform available from Xpansion Instruments LLC,Tallmadge, Ohio, USA. The SER Testing Platform was used on a RheometricsARES-LS (RSA3) strain-controlled rotational rheometer available from TAInstruments Inc., New Castle, Del., USA. The SER Testing Platform isdescribed in U.S. Pat. Nos. 6,578,413 and 6,691,569, which areincorporated herein for reference. A general description of transientuniaxial extensional viscosity measurements is provided, for example, in“Strain hardening of various polyolefins in uniaxial elongational flow,”The Society of Rheology, Inc., J. Rheol. 47(3), 619-630 (2003); and“Measuring the transient extensional rheology of polyethylene meltsusing the SER universal testing platform,” The Society of Rheology,Inc., J. Rheol. 49(3), 585-606 (2005), incorporated herein forreference. Strain hardening occurs when a polymer is subjected touniaxial extension and the transient extensional viscosity increasesmore than what is predicted from linear viscoelastic theory. Strainhardening is observed as abrupt upswing of the extensional viscosity inthe transient extensional viscosity vs. time plot. A strain hardeningratio (SHR) is used to characterize the upswing in extensional viscosityand is defined as the ratio of the maximum transient extensionalviscosity over three times the value of the transient zero-shear-rateviscosity at the same strain. Strain hardening is present in thematerial when the ratio is greater than 1.

Comonomer content (such as for butene, hexene, and octene) wasdetermined via FTIR measurements according to ASTM D3900 (calibratedversus ¹³C NMR). A thin homogeneous film of polymer, pressed at atemperature of about 150° C., was mounted on a Perkin Elmer Spectrum2000 infrared spectrophotometer. The weight percent of copolymer isdetermined via measurement of the methyl deformation band at ^(˜)1375cm-1. The peak height of this band is normalized by the combination andovertone band at ^(˜)4321 cm-1, which corrects for path lengthdifferences.

Peak melting point, Tm (also referred to as melting point), peakcrystallization temperature, Tc (also referred to as crystallizationtemperature), glass transition temperature (Tg), heat of fusion (ΔHf orHf), and percent crystallinity were determined using the following DSCprocedure according to ASTM D3418-03. Differential scanning calorimetric(DSC) data were obtained using a TA Instruments model Q200 machine.Samples weighing approximately 5-10 mg were sealed in an aluminumhermetic sample pan. The DSC data were recorded by first graduallyheating the sample to 200° C. at a rate of 10° C./minute. The sample waskept at 200° C. for 2 minutes and then cooled to −90° C. at a rate of10° C./minute, followed by an isothermal for 2 minutes and heating to200° C. at 10° C./minute. Both the first and second cycle thermal eventswere recorded. Areas under the endothermic peaks were measured and usedto determine the heat of fusion and the percent of crystallinity. Thepercent crystallinity is calculated using the formula, [area under themelting peak (Joules/gram)/B (Joules/gram)]*100, where B is the heat offusion for the 100% crystalline homopolymer of the major monomercomponent. These values for B are to be obtained from the PolymerHandbook, Fourth Edition, published by John Wiley and Sons, New York1999, provided; however, that a value of 189 J/g (B) is used as the heatof fusion for 100% crystalline polypropylene, a value of 290 J/g is usedfor the heat of fusion for 100% crystalline polyethylene. The meltingand crystallization temperatures reported here were obtained during thesecond heating/cooling cycle unless otherwise noted.

For polymers displaying multiple endothermic and exothermic peaks, allthe peak crystallization temperatures and peak melting temperatures werereported. The heat of fusion for each endothermic peak was calculatedindividually. The percent crystallinity is calculated using the sum ofheat of fusions from all endothermic peaks. Some of polymer blendsproduced show a secondary melting/cooling peak overlapping with theprincipal peak, which peaks are considered together as a singlemelting/cooling peak. The highest of these peaks is considered the peakmelting temperature/crystallization point. For the amorphous polymers,having comparatively low levels of crystallinity, the meltingtemperature is typically measured and reported during the first heatingcycle. Prior to the DSC measurement, the sample was aged (typically byholding it at ambient temperature for a period of 2 days) or annealed tomaximize the level of crystallinity.

Unless otherwise stated, polymer molecular weight (weight-averagemolecular weight, Mw, number-average molecular weight, Mn, andZ-averaged molecular weight, Mz) and molecular weight distribution(M_(w)/M_(n)) are determined using Size-Exclusion Chromatography.Equipment consists of a High Temperature Size Exclusion Chromatograph(either from Waters Corporation or Polymer Laboratories), with adifferential refractive index detector (DRI), an online light scatteringdetector, and a viscometer. Three Polymer Laboratories PLgel 10 mmMixed-B columns are used. The nominal flow rate is 0.5 cm³/min and thenominal injection volume is 300 μL. The various transfer lines, columnsand differential refractometer (the DRI detector) are contained in anoven maintained at 135° C. Solvent for the SEC experiment is prepared bydissolving 6 grams of butylated hydroxy toluene as an antioxidant in 4liters of reagent grade 1,2,4 trichlorobenzene (TCB). The TCB mixture isthen filtered through a 0.7 μm glass pre-filter and subsequently througha 0.1 μm Teflon filter. The TCB is then degassed with an online degasserbefore entering the SEC.

Polymer solutions are prepared by placing dry polymer in a glasscontainer, adding the desired amount of TCB, then heating the mixture at160° C. with continuous agitation for about 2 hours. All quantities aremeasured gravimetrically. The TCB densities used to express the polymerconcentration in mass/volume units are 1.463 g/ml at room temperatureand 1.324 g/ml at 135° C. The injection concentration can range from 1.0to 2.0 mg/ml, with lower concentrations being used for higher molecularweight samples.

Prior to running each sample, the DRI detector and the injector arepurged. Flow rate in the apparatus is then increased to 0.5 ml/minute,and the DRI allowed to stabilize for 8 to 9 hours before injecting thefirst sample. The LS laser is turned on 1 to 1.5 hours before runningsamples.

The concentration, c, at each point in the chromatogram is calculatedfrom the DRI signal after subtracting the prevailing baseline, I_(DRI),using the following equation:c=K _(DRI) I _(DRI)/(dn/dc)where K_(DRI) is a constant determined by calibrating the DRI, and(dn/dc) is the same as described below for the LS analysis. Theprocesses of subtracting the prevailing baseline (i.e., backgroundsignal) and setting integration limits that define the starting andending points of the chromatogram are well known to those familiar withSEC analysis. Units on parameters throughout this description of the SECmethod are such that concentration is expressed in g/cm³, molecularweight is expressed in g/mole, and intrinsic viscosity is expressed indL/g.

The light scattering detector is a Wyatt Technology High Temperaturemini-DAWN. The polymer molecular weight, M, at each point in thechromatogram is determined by analyzing the LS output using the Zimmmodel for static light scattering (M. B. Huglin, LIGHT SCATTERING FROMPOLYMER SOLUTIONS, Academic Press, 1971):

$\frac{K_{O}c}{\Delta\;{R(\theta)}} = {\frac{1}{{MP}(\theta)} + {2\; A_{2}{c.}}}$Here, ΔR(θ) is the measured excess Rayleigh scattering intensity atscattering angle θ, c is the polymer concentration determined from theDRI analysis, A₂ is the second virial coefficient, P(θ) is the formfactor for a monodisperse random coil (described in the abovereference), and K_(o) is the optical constant for the system:

$K_{O} = \frac{4\;\pi^{2}{n^{2}\left( \frac{\mathbb{d}n}{\mathbb{d}c} \right)}^{2}}{\lambda^{4}N_{A}}$in which N_(A) is Avogadro's number, and (dn/dc) is the refractive indexincrement for the system. The refractive index, n=1.500 for TCB at 135°C. and λ=690 nm. In addition, A₂=0.0015 and (dn/dc)=0.104 forpolyethylene in TCB at 135° C.; both parameters may vary with averagecomposition of an ethylene copolymer. Thus, the molecular weightdetermined by LS analysis is calculated by solving the above equationsfor each point in the chromatogram; together these allow for calculationof the average molecular weight and molecular weight distribution by LSanalysis.

A high temperature Viscotek Corporation viscometer is used, which hasfour capillaries arranged in a Wheatstone bridge configuration with twopressure transducers. One transducer measures the total pressure dropacross the detector, and the other, positioned between the two sides ofthe bridge, measures a differential pressure. The specific viscosity forthe solution flowing through the viscometer at each point in thechromatogram, (η_(s))_(i), is calculated from the ratio of theiroutputs. The intrinsic viscosity at each point in the chromatogram,[η]_(i), is calculated by solving the following equation (for thepositive root) at each point i:(η_(s))_(i) =c _(i)[η]_(i)+0.3(c _(i)[η]_(i))²where c_(i) is the concentration at point i as determined from the DRIanalysis.

The branching index (g′_(vis)) is calculated using the output of theSEC-DRI-LS-VIS method (described above) as follows. The averageintrinsic viscosity, [η]_(avg), of the sample is calculated by:

$\lbrack\eta\rbrack_{avg} = \frac{\sum{c_{i}\lbrack\eta\rbrack}_{i}}{\sum c_{i}}$where the summations are over the chromatographic slices, i, between theintegration limits. The branching index g′ is defined as:

$g_{vis}^{\prime} = \frac{\lbrack\eta\rbrack_{avg}}{{kM}_{v}^{\alpha}}$where the Mark-Houwink parameters k and α are given by k=0.00592,a=0.463. The hydrogenated polybutadiene based modifier can berepresented as a butane copolymer for these calculations with 12%butene. M_(v) is the viscosity-average molecular weight based onmolecular weights determined by LS analysis.

Experimental and analysis details not described above, including how thedetectors are calibrated and how to calculate the composition dependenceof Mark-Houwink parameters and the second-virial coefficient, aredescribed by T. Sun, P. Brant, R. R. Chance, and W. W. Graessley(Macromolecules, 2001 volume 34(19), pages 6812-6820).

Proton NMR spectra were collected using a 500 MHz Varian pulsed fouriertransform NMR spectrometer equipped with a variable temperature protondetection probe operating at 120° C. The polymer sample is dissolved in1,1,2,2-tetrachloroethane-d2 (TCE-d2) and transferred into a 5 mm glassNMR tube. Typical acquisition parameters are sweep width=10 KHz, pulsewidth=30 degrees, acquisition time=2 s, acquisition delay=5 s and numberof scans=120. Chemical shifts are determined relative to the TCE-d2signal which is set to 5.98 ppm.

In conducting the ¹³C NMR investigations, samples are prepared by addingabout 0.3 g sample to approximately 3 g of tetrachloroethane-d2 in a 10mm NMR tube. The samples are dissolved and homogenized by heating thetube and its contents to 150° C. The data are collected using a Varianspectrometer, with corresponding ¹H frequencies of either 400 or 700 MHz(in event of conflict, 700 MHz shall be used). The data are acquiredusing nominally 4000 transients per data file with a about a 10 secondpulse repetition delay. To achieve maximum signal-to-noise forquantitative analysis, multiple data files may be added together. Thespectral width was adjusted to include all the NMR resonances ofinterest and FIDs were collected containing a minimum of 32K datapoints. The samples are analyzed at 120° C. in a 10 mm broad band probe.

Where applicable, the properties and descriptions below are intended toencompass measurements in both the machine and transverse directions.Such measurements are reported separately, with the designation “MD”indicating a measurement in the machine direction, and “TD” indicating ameasurement in the transverse direction.

EXAMPLES

All reactions in the following examples were performed using as-receivedstarting materials without any purification.

Example 1

A reaction flask was charged with trimethylolpropane triacrylate (TMPTA)and cyclooctene (COE) at a molar ratio of 10:1143. An appropriate amountof dichloromethane (DCM) was then added to make the concentration of COEas 0.4 M. The solution was stirred by a magnetic stirrer. A small volumeof Grubbs 2nd generation catalyst solution in DCM (1 milliliter) wasprepared and injected into the stirred monomer solution. The reactionmixture was stirred at 40° C. under slow nitrogen flow for 16 hoursbefore it was quenched by several drops of ethyl vinyl ether. Silica gelwas then added and the mixture was stirred overnight at roomtemperature. The reaction mixture was filtered and the filtrate wasconcentrated followed by precipitation to methanol. The reaction schemeis shown in FIG. 2. The polymer product obtained after filtration anddrying as an off-white solid with high yields. The structure of thepolymer was determined by ¹H NMR as shown in FIG. 3. In this Example, aseries of catalyst loadings ([COE/Catalyst] varied from 54 to 3456) wereexamined and the relationships between linker length, insertionefficiency (measured by T3/T2) and catalyst loading are illustrated inFIG. 4.

In FIG. 3, ¹H NMR clearly shows the signature pair of protons e and d,indicating the new double bond formed between the acrylic connector andpolycyclooctene linker. No homocoupled acrylic connectors were observed.There was a small amount of unreacted acrylic double bonds, implyingsome acrylic connectors were partially inserted into the linkers (T2)and some were at the chain ends (T1). A full insertion means all thethree double bonds of a TMPTA molecule were reacted (T3) and it is thedesired pathway to dendritic structures. The average linker length wascalculated by the integral ratio of protons f and d. It is unable todistinguish T1 and T2 from ¹H NMR. In order to estimate the insertionefficiency, an assumption was made that all the partially inserted TMPTAmolecules were T2-type. The T3/T2 ratio was then used as the indicationof insertion efficiency. Higher T3/T2 means more fully insertedconnectors and thus more completed dendritic structures. This is aconservative estimation because less T1 (a T1 moiety has 2 unreactedacrylic double bonds) is needed to account for the same amount ofterminal acrylic double bonds than T2 (a T2 moiety has only 1 unreactedacrylic double bond). If the insertion efficiency is calculated asT3/(T2+T1), the value will be higher than T3/T2.

Example 2

The series of reactions performed in this Example demonstrates that onecan control the average linker length and insertion efficiency simply byadjusting the catalyst loading. As illustrated in FIG. 4, linker lengthincreases along with the decrease of catalyst loading. At the same time,a high full insertion ratio can be achieved at a certain catalystloading. The relationships shown in FIG. 4 can also guide the synthesisof dendritic structures with desired linker length and dendriticgeneration (or degree of hyperbranching).

A reaction flask was charged with 60 mmol cyclooctene (COE), 0.363 mmolpentaerythritol tetraacrylate (PETA), and 20 milliliters of toluene. Thesolution was stirred by a magnetic stirrer. A small volume of 85milligrams of Grubbs 2nd generation catalyst solution in toluene (1milliliter) was prepared and injected into the stirred monomer solution.The reaction mixture was stirred at 60° C. under slow nitrogen flow for16-48 hours before it was quenched by several drops of ethyl vinylether. During the synthesis, no gels were formed. A small amount ofreaction mixture was taken out by syringe and dried for NMR and GPCanalyses. To the same reaction flask, excess p-toluenesulfonhydrazide(TSH, normally 3 equivalents to olefins), 10-40 milligrams butylatedhydroxy toluene (BHT), and 150 milliliters toluene were added. Themixture was heated to reflux followed by an injection of excesstri-n-propylamine (TPA, normally 3 equivalents to olefins). Afterrefluxing for 4 hours, the mixture was poured into 1.5 liter methanolwhile it was still hot. The white precipitate was filtered and washedwith 100 milliliters of methanol three times. The reaction scheme isshown in FIG. 5. The fully hydrogenated dendritic polyethylene, DPEY,was obtained as white solid with high yields. The polymer beforehydrogenation was soluble in CDCl₃ at room temperature and the polymerafter hydrogenation was soluble in o-dichlorobenzene-d₄ (o-DCB-d₄) atelevated temperatures (100° C.). The two ¹H NMR spectra were stacked inFIG. 6 for comparison.

As shown in FIG. 6, in the unsaturated polymer (top/red spectrum), PETAmolecules were almost all fully inserted, indicated by protons a and b,and negligible unreacted terminal acrylic double bonds. Afterhydrogenation (bottom/blue spectrum), all the alkene protons disappearedand ester linkages preserved. GPC analysis showed the unsaturatedpolymer had an Mw of 246,000 g/mol and Mw/Mn of 12.6 (refractive indexdetector with reference to polyisobutylene standards), and the fullyhydrogenated dendritic polyethylene, DPEY, had an Mw of 200,000 g/moland Mw/Mn of 10 (light scattering detector with reference to linearpolyethylene standards). The branching index g′ of DPEY was found to be0.42 by GPC-3D, suggesting a highly branched structure. The massrecovery of GPC was nearly quantitative, indicating no gel presence inthe synthesis. Differential Scanning calorimetry (DSC) showed themelting point of the DPEY was 128° C. and its crystallinity was 66%.This synthesis can be scaled up to kilogram scale by utilizing largereaction vessel and mechanical stirrer.

The same reaction performed by utilizing a mechanical stirrer yielded adendritic PE with the same chemical composition but higher molecularweight and lower branching index. The fully hydrogenated dendriticpolyethylene, DPEY2, synthesized by mechanical stirring had Mw of327,000 g/mol (light scattering detector with reference to linearpolyethylene standards). Its branching index g′ was determined to be0.31 by GPC-3D, indicating an even higher branched structure. DSC showedthe melting point of DPEY2 is 127° C. and its crystallinity is 67%.

The dendritic PEs demonstrated excellent thermal stability confirmed byboth Thermal Gravimetric Analysis (TGA) and rheology. As shown in theFIG. 7, DPEY2 exhibits extensional hardening with a large strainhardening ratio (SHR) of 30.

The same reaction performed by utilizing a mechanical stirrer and ablend of toluene and THF as solvent (1:1 v/v ratio), rather than toluenealone, yielded a dendritic PE with the same chemical composition buthigher molecular weight and lower branching index. The fullyhydrogenated dendritic polyethylene, DPEY3, had Mw of 222,000 g/mol(light scattering detector with reference to linear polyethylenestandards). Its branching index g′ was determined to be 0.35 by GPC-3D,indicating an even higher branched structure. DSC showed the meltingpoint of DPEY3 is 127° C. and its crystallinity is 66%.

Example 3

A reaction flask was charged with 12 mmol cyclooctene (COE), 48 mmol1,5-dimethylcyclooctadiene (DMCOD), 0.363 mmol tetraacrylate PETA, and17 milliliters of toluene. The solution was stirred by a magneticstirrer. A small volume of 85 milligrams of Grubbs 2nd generationcatalyst solution in toluene (1 milliliter) was prepared and injectedinto the stirred monomer solution. The reaction mixture was stirred at60° C. under slow nitrogen flow for 16-48 hours before it was quenchedby several drops of ethyl vinyl ether. Silica gel was then added and themixture was stirred overnight at room temperature. The reaction mixturewas filtered and the filtrate was concentrated followed by precipitationto methanol. The reaction scheme is shown in FIG. 10. The polymerproduct was received after filtration and drying as an off-white gummysolid with high yields. The structure of the polymer was determined by¹H NMR as shown in FIG. 11. GPC analysis showed the unsaturated polymerhad Mw of 116 kDa and PDI of 7.6 (refractive index detector withreference to polyisobutylene standards). DSC showed no obvious meltingpoint. As shown in FIG. 11, ¹H NMR confirmed almost all the PETAconnectors were fully inserted into the copolymer of COE and DMCOD.After hydrogenation, an amorphous 50/50 (wt/wt) dendritic EP copolymeris expected and can be used as a viscosity index improver in lubricantoils. The synthesis can be scaled up to kilogram scale by utilizinglarge reaction vessel and mechanical stirrer. To make amorphousdendritic POs, cyclic olefins other than DMCOD, such as norbornene orits derivatives, can be employed.

The properties of the Modifiers are described in Table A.

TABLE A Linker Mw crystallinity length Modifier (g/mol) Mw/Mn g′ Tm (°C.) (%) (g/mol) Example 2* 246,000 12.6 DPEY 200,000 10 0.42 128 6612,000 DPEY2 327,000 9 0.31 127 67 12,000 Example 3* 116,000 7.6 DPEY3222,000 10 0.35 127 66 8,000 *not hydrogenatedPolyethylene Blends—1

When Exceed™ Linear Low Density Polyethylene (LLDPE) 2018 was blendedwith DPEY2 at 1 wt % and 3 wt %, extensional hardening was found in theblends, as shown in FIG. 8, in contrast to the observation that noextensional hardening can be seen in Exceed™ LLDPE 2018 alone. DSCtraces of DPEY, Exceed™ LLDPE and blends of Exceed containing 1% DPEYare shown in FIG. 9. Addition of DPEY to Exceed™ LLDPE 2018 at 1% didnot alter or affect the LLDPE crystallization behavior. Both DPEY andDPEY2 are miscible and compatible with LLDPE and are able toco-crystallize with LLDPE. The blends were made as follows:

The dendritic PE modifier, DPEY or DPEY2, prepared as described above,was blended with Exceed™ 2018 Polyethylene (a linear m-LLDPE, ExxonMobilChemical Company, Houston Tex., 0.918 g/cc, MI of 2 dg/min (190° C.,2.16 kg), Mw of about 94,000 g/mol, an Mw/Mn of about 2, g′ vis of 0.97,a hexene content of about 6.0 wt %, and a CDBI of about 82% to 85%)using a DSM twin-screw miniature extrusion mixer running at 180° C. to185° C., 50 RPM, and for 3 minutes. 0.1 wt % of BHT stabilizer wasadded. The blend was compression molded at 190° C. for 10 minutes at 15t to prepare testing plaques. A SER2 (Sentmanat Extensional Rheometer 2)attachment on an ARES rheometer was used to measure the extensionalstrain hardening of these plaques at 150° C. Strain hardening could befound for the blend sample containing the modifier in contrast to theobservation that no extensional hardening can be seen in Exceed™ 2018Polyethylene.

Polyethylene Blends—2

Prior to blowing film, the minor component and matrix polyethylene werecompounded in a 1″ Haake twin screw extruder. The Haake twin screwextruder was set at 50 rpm and the melt temperature was targeted at 190°C. The blown film experiments were conducted on a Haake blown film linecontaining a 1″ single screw extruder and a 1″ mono-layer blown filmdie. The single screw has a Maddock mixing session. The pure resin orthe blends were fed into the 1″ single screw extruder to be melted andhomogenized. The molten polymer was pressurized and fed into a 1″tubular die. The annular die forms an annular shape with the moltenpolymer melt with even flow distribution around its circumference. Uponexiting the die lip, two streams of air were introduced to blow thepolymer melt into a tubular form, commonly called a bubble, andsubsequently to cool the thin film. One stream of air was introduced inthe center of the die to inflate the bubble to a certain diameter, orblowup ratio (BUR). The BUR is defined as:BUR=2×L/(π×D)where D is the die diameter and L is the film bubble lay flat width.

For all the experiments, the BUR is the same and is set at 2.8. The filmgauge is 1.5 mil. (The film had a lay flat of 4.4 inches (11.2 cm), anextruder speed of 33 rpm, and extrusion temperatures in zones 1, 2, 3,and 5 (die) were 190° C., 195° C., 190° C., and 185° C., respectively.)

The tube or bubble collapsed after reaching the two up-nip rollers. Thenip rollers are driven by a motor with varied speeds. The film wassolidified prior to reach the up-nip rollers. The film was collectedafter passing through the up-nip rollers. The thickness of the film iscontrolled by speed of the nip rollers.

A comparative blend/film of Exceed™ 2018 PE combined with 5 wt % LDPE(ExxonMobil Chemical Company, Houston, Tex. LD071.LR™ PE, 0.924 g/cc,0.70 dg/min, 190° C., 2.16 kg) and 0.1 wt % BHT was also prepared underthe conditions described above (referred to as Blend C). The blendcompositions and film properties are listed in Table 1. The 1% modifierblends produce gel-free films with the excellent optics. The haze valueis reduced from 43.2% for Exceed™ 2018 PE to 5.9% for the blend. One ofthe blown film processability measurements is the film gauge variationas measured by the coefficient of variation (COV). Blend B shows lowergauge COV compared to Blend A. Blend B also retains most of themechanical properties except dart impact strength, which is lower thanBlend A but higher than the Exceed™ 2018 PE blend with 5% LDPE. Althoughthe 5% LDPE blend improved the gauge COV and optical properties, thedart impact strength was reduced significantly.

TABLE 1 Blend A Blend B Blend C Blend D Exceed ™ LLDPE 2018 99.9 wt %98.9 wt % 94.9 wt % 98.9 wt % Modifier 0 wt % 1 wt % DPEY LDPE 5 wt % 1wt % DPEY2 BHT 0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt % 1% Secant Modulus(MD) psi 25,986 27,453 28940 25847 1% Secant Modulus (TD) psi 23,72930,751 28503 28711 Tensile Strength at Yield (MD) psi 1212 1306 13041371 Tensile Strength at Yield(TD) psi 1211 1473 1396 1575 Elongation atYield (MD) % 6 7.4 6 7 Elongation at Yield (TD) % 5 6.7 6 7 TensileStrength (MD) psi 8437 7675 7564 7505 Tensile Strength (TD) psi 76477157 7326 7782 Elongation at Break (MD) % 686 687 697 682 Elongation atBreak (TD) % 677 643 664 678 Elmendorf Tear (MD) g 456 417 ElmendorfTear (TD) g 523 Elmendorf Tear (MD) g/mil 338 333 259 367 Elmendorf Tear(TD) g/mil 414 414 437 Dart Drop (g) 517 365 Dart Drop (g/mil) 410 304230 203 Haze (%) 43.2 5.9 16.7 5.7 Internal Haze (%) 1.4 Gauge COV (%)12.5 9.125 7.1 8.4

When the molecular weight of the modifier was increased from 200,000g/mol to 327,000 g/mol, the 1% modifier (DPEY2) blend exhibited improvedMD/TD tear properties. Both MD tear and TD tear were improved by 5-9% incomparison to neat Exceed™ 2018 PE film, while the MD tear of 5% LDPEblend was reduced by 23% in comparison to neat Exceed™ 2018 PE film.

It was also observed that the 100% Exceed™ 2018 PE bubble was unstablewhile the bubble with 1% addition of Modifier, DPEY, or DPEY2 wasstable.

All documents described herein are incorporated by reference herein forpurposes of all jurisdictions where such practice is allowed, includingany priority documents, related applications, and/or testing proceduresto the extent they are not inconsistent with this text, provided howeverthat any priority document not named in the initially filed applicationor filing documents is NOT incorporated by reference herein. As isapparent from the foregoing general description and the specificembodiments, while forms of the invention have been illustrated anddescribed, various modifications can be made without departing from thespirit and scope of the invention. Accordingly, it is not intended thatthe invention be limited thereby. Likewise, the term “comprising” isconsidered synonymous with the term “including” for purposes ofAustralian law. Likewise whenever a composition, an element or a groupof elements is preceded with the transitional phrase “comprising,” it isunderstood that we also contemplate the same composition or group ofelements with transitional phrases “consisting essentially of,”“consisting of,” “selected from the group of consisting of,” or “is”preceding the recitation of the composition, element, or elements andvice versa.

The invention claimed is:
 1. A polyethylene blend comprising one or moreethylene polymers and one or more dendritic hydrocarbon polymermodifiers, wherein the modifier has: 1) a g′_(vis) value less than 0.75;2) at least 0.6 ppm ester groups as determined by ¹H NMR; 3) a Tm of100° C. or more; 4) an Mw of 50,000 g/mol or more, as determined by GPC;and 5) an average number of carbon atoms between branch points of 70 ormore as determined by ¹H NMR.
 2. The composition of claim 1, wherein themodifier has 5 wt % or less of xylene insoluble material.
 3. Thecomposition of claim 1, wherein the modifier has a weight averagemolecular weight between the branch points of 1,000 g/mol or more. 4.The composition of claim 1, wherein the modifier is present at 0.25 wt %to 10 wt %, based upon the weight of the blend.
 5. The composition ofclaim 1, wherein the polyethylene comprises a copolymer of ethylene andone or more C₃ to C₂₀ alphaolefins and has an M_(W) of 20,000 to1,000,000 g/mol.
 6. The composition of claim 1, wherein the polyethylenehas a density of 0.91 to 0.96 g/cm³.
 7. The composition of claim 1,wherein the modifier is present at from 0.1 wt % to 5 wt % (based uponthe weight of the blend), and the polyethylene has a compositiondistribution breadth index of 60% or more and a density of 0.90 g/cc ormore.
 8. The modifier of claim 1, wherein the modifier has astrain-hardening ratio of 2 or more and the blend has a strain hardeningratio of greater than 1.0.
 9. A polyethylene film comprising the blendof claim 1, said film having a gauge variation that is at least 10%lower than that of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions anda dart impact strength that is within 20% of a film of the samethickness and of the same composition, absent the modifier, preparedunder the same conditions.
 10. A polyethylene film comprising the blendof claim 1, said film having a gauge variation that is at least 10%lower than that of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions anda MD Tear strength that is within 20% of a film of the same thicknessand of the same composition, absent the modifier, prepared under thesame conditions.
 11. A polyethylene film comprising the blend of claim1, said film having a haze that is at least 10% lower than that of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions and a dart impact strengththat is within 20% of a film of the same thickness and of the samecomposition, absent the modifier, prepared under the same conditions.12. A polyethylene film comprising the blend of claim 1, said filmhaving a haze that is at least 10% lower than that of a film of the samethickness and of the same composition, absent the modifier, preparedunder the same conditions and a MD Tear strength that is within 20% of afilm of the same thickness and of the same composition, absent themodifier, prepared under the same conditions.
 13. A film comprising thecomposition of claim 1, said film having a haze of 10% or less.
 14. Afilm comprising the composition of claim 1, wherein the film has a hazethat is at least 10% less than the haze measured on a film of the samethickness and of the same composition, absent the dendritic hydrocarbonpolymer modifier, prepared under the same conditions.
 15. A filmcomprising the composition of claim 1, wherein the film has a gaugevariation that is at least 10% less than the gauge variation measured ona film of the same thickness and of the same composition, absent thedendritic hydrocarbon polymer modifier, prepared under the sameconditions.
 16. A film comprising the composition of claim 1, whereinthe film has a dart impact strength that is greater than or within 30%less than the dart impact strength measured on a film of the samethickness and of the same composition, absent the dendritic hydrocarbonpolymer modifier, prepared under the same conditions.
 17. A filmcomprising the composition of claim 1, wherein the film has an MD Tearstrength that is greater than or within 30% less than the MD Tearstrength measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions.
 18. A film comprising the blend of claim 1,wherein the film has a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions, and the film has a Dart Drop, ing/mil, that within 30% of the Dart Drop measured on a film of the samethickness and of the same composition, absent the dendritic hydrocarbonpolymer modifier, prepared under the same conditions.
 19. A filmcomprising the blend of claim 1, wherein the film has a gauge variationthat is at least 10% less than the gauge variation measured on a film ofthe same thickness and of the same composition, absent the dendritichydrocarbon polymer modifier, prepared under the same conditions, andthe film has an MD Tear strength that is greater than or within 30% lessthan the MD Tear strength measured on a film of the same thickness andof the same composition, absent the dendritic hydrocarbon polymermodifier, prepared under the same conditions.
 20. A film comprising theblend of claim 1, wherein the blend composition has a strain hardeningratio that is at least 10% greater than the strain hardening ratiomeasured on a composition, absent the dendritic hydrocarbon polymermodifier, and the film has a Dart Drop, in g/mil, that within 30% of theDart Drop measured on a film of the same thickness and of the samecomposition, absent the dendritic hydrocarbon polymer modifier, preparedunder the same conditions.
 21. A film comprising the blend of claim 1,wherein the film has a gauge variation that is at least 10% less thanthe gauge variation measured on a film of the same thickness and of thesame composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions, and the film has a haze that is atleast 10% less than haze measured on a film of the same thickness and ofthe same composition, absent the dendritic hydrocarbon polymer modifier,prepared under the same conditions.
 22. The composition of claim 1comprising more than 25 wt % (based on the weight of the composition) ofone or more ethylene polymers having a g′_(vis) of 0.95 or more and anM_(W) of 20,000 g/mol or more and at least 0.1 wt % of the dendritichydrocarbon polymer modifier where the modifier has a g′_(vis) of lessthan 0.75, wherein the ethylene polymer has a g′_(vis) of at least 0.25units higher than the g′_(vis) of the branched modifier.
 23. Thecomposition of claim 1, wherein the modifier has a shear thinning ratioof complex viscosity at a frequency of 0.01 rad/sec to the complexviscosity at a frequency of 398 rad/sec greater than 53.9*I2^((−0.74)),where I2 is the melt index according to ASTM 1238 D, 190° C., 2.16 kg.